Something simple anyone can do at home too. You might like this video which takes the same approach for another topic 🤓 th-cam.com/video/SzYkIhuDDcc/w-d-xo.html
The much maligned and disrespected "cheap knock-off" displayed a feat of supernatural toughness, strength. Even brutal torture could not break its resolve. Applause for the underdog. Thanks for the demo on materials science. I'm always enjoy learning something new from your videos.
@@Cortesevasive Decent customer service for sure. Not free, but convenient. The fact that the program is so well known and well established means they ship a lot if these. (If it was very rare, then they could just eat the shipping on those rare occasions.)
After 7yrs of regular use, one of my 3 ECOs developed a hairline crack in the section. $5 got me a new pen body. I've wondered if new hobbiests are applying too much pressure on the nib, which in turn is adding significant stresses to the section. That and the fact that the ECO has become a phenom in terms of units sold (so we hear about a lot more cracks because they're selling a ton more pens). Dunno for sure, and back when the ECO first launched, there were a lot of reports that the cracking was due to stress introduced by the manufacturing process. Thanks very much for sharing the video. Nice work!
I once had a project where I had to write a cleaning specification for cast acrylic slabs 10 feet long, 5 feet wide and five inches thick. In researching compatible solvents / claening materials for these slabs, I was shocked at the high number of organic solvents and cleaning compounds that will attack acrylic. The primary indication of chemical attack is crazing / cracking at stress concentration areas and where internal stresses are high. The only cleaner I could suggest was a mild dish detergent and soft water. I'm not certain, but there may be certain additives in some inks that attack some acrylics used for pen bodies. Inks can contain surfactants, viscosity modifiers, preservatives, scents and perhaps other propriety ingredients that alone, or in combination may be incompatible with pen bodies in acrylic.
My first three pens I bought about four years ago now were a Pilot metropolitan, TWSBI GO, and TWSBI ECO. I was new to pens and wanted to use them at work. I work at a fast paced environment, capping and uncapping my pen hundreds of times in a day and setting it down not so carefully on a hard counter. I dropped my metro and busted the nib (oops but not a great loss to me honestly) and my ECO DID develop a hairline crack right where you pointed out on your video after I had taken the nib and feed out to clean it. I still use it often since it really hasn’t affected it, albeit a little more carefully. My GO is GOing strong and I still use it daily at work without any cracks or problems. It’s my daily “chuck it around” carry. I have since bought two ECOs and haven’t had any problems at all, likely because I have no need to remove the nibs and have treated them nicer than the me of four years ago. That has been my limited experience! I think had I had less micro impacts from setting my TWSBI down in a rush all day and had I not removed the nib, I wouldn’t have had a crack.
The two TWSBI pens I have had crack were the original limited eco they did in the turquoise, and the vac 700R iris. On the eco it is around the collar where you observed the pressure points on yours, and I never removed the nib. It was from the pressure of writing. That pen isn't with me right now, but I have in my hands the cracked vac 700 Iris, where the cracks are on the cap threads, on the end where the whole nib unit screws into the barrel, but the vac 700 cap is cushioned in a way the eco isn't. I emptied that pen twice before they showed up. I have a replacement barrel now, that I have been waiting for the third fill to get used to replace it. In both cases the cracks are vertical, which suggests to me they are from lateral pressure and not torsion, but maybe with how small the cracks are the two would present the same way. Part of the issue is going to be what TWSBI is using for the material. In order to make it crystal clear, it's inflexible, unlike the chinese pen. It's very brittle. The rest of my Ecos were fine before I sold them on (the japan exclusive orange, china exclusive pink and blue, a couple other limited ecos and two eco-t's - for awhile I was collecting every solid color they made as it came out), and I've never had any of their other pens. And I think you actually hear about it happening _less_ than it actually does, because of TWSBI's replacement policy. The pens aren't going to go back to a retailer, and TWSBI has no incentive to release real failure rates when they can just say, "Fake news." I think that you are probably right about the overall failure rate being low, but considering the sheer volume of production TWSBI does, that can still be a large number of pens. Say they have produced a million pens across all of their product lines over the past ten years and the failure rate is 1% - thats still _thousands_ of pens that fail.
Very informative, thanks. I have two TWSBI Ecos (one , one ) - I really love their capacity, looks, and nibs . I've had both pens for about 2 years, they rarely leave home and I treat all of my things with care. Yet both of them developed cracks at the top of the section near where the nib enters the pen, just like you showed, which is very disappointing as I consider them some of my favorite pens. I never pulled the nib/feed out of the pen for cleaning, so that's not it.
@@levon9 some of my pens have had super duper tight feeds from the factory. There is no need for it. In fact, just removing the feed risks damaging it sometimes when it is that tight
It didn't work very well, cap has rust from the screw, threads were chewy, brush unit would almost fall out from the of the body it was so loose, and the piston action was terrible.... but the little f**cker can take a BEATING!
Between 2017 and 2018 I had 4 TWSBI Ecos, from 4 different online vendors - 3 developed cracks in the section. The first 2 I used heavily for writing notes and drawing ( I use my pens primarily for art), the last 2 I babied alot but #3 still developed a crack so I sold off #4. Afterwards I used alot of cheap wingsung pens (3009, 3008, 3003) and they held up way longer than the Ecos - and I wasn't as careful with them cause I figured they would break but at least they are only $5 each instead of $30. With the TWSBI, I agree that it is/was a tolerance problem with the opening being too small for the friction fit nib and feed, but the whole experience soured me on the pen. It's possible they did improve the resin but who knows when the "bad batch" was and how much old stock still remains. That is probably why it still is being reported regularly - they didn't do a recall but they just send you a new (hopefully improved) barrel for the cost of shipping.
Yep. I am recently on my second replacement because of the same issue; cracks in the section lip. So I thought I might have been too rough taking the feed out and putting it back in. Now I know it's not my fault. Just as you, I am off TWSBI.
Love watching you science the heck out of a pen person’s eternal questions! Another aspect I wonder about: vulnerability of various plastics to chemical residues on our fingers, particularly ethyl alcohol. The cap of a TWSBI Classic I have (different type of plastic) completely disintegrated on me a few years ago; I realized it may have had to do with a brief Purell exposure (and Philip of TWSBI confirmed that this could be an issue). So I wonder about the section of the pen, and exposure to still-moist, ‘decontaminated’ "fingers. Clearly, this is not the sole cause. (I’m also recalling Waskisquirrel’s beloved Pilot Custom 823, whose barrel became completely crazed through exposure to a household cleaning liquid.)
Yeah other chemicals reacting is definitely a possibility. I'm leaning towards stresses during the manufacturing stage somewhere along the line. There's so many variables to pin down but this would be a project if love to do. My favorite thing to do was track down a problem or solution, especially when it was strange & obscure. Spent a week tracking down an issue with a precision motion system and it turned out to be caused by a slight deviation in the finish on a pair of stainless steel guide shafts. I love the creative part of the problem solving process. Keeps it fun
Can't believe I forgot about this method for so long and it was finally my wife's cracked tooth that reminded me! There is proper gear I could have ordered to make this a better setup but I did it this way so almost anyone can do this themselves.
I came back because I forgot to give you a thumbs up for using bifringence to visualize those internal stresses. It's wonderful to see the vast reaches of techniques I saw in school used to answer relevant questions surrounding our inky hobby. 👍😁
Yuppers, just have to remember all that stuff which is the hardest part. There's so much info out there it's tough to remember it all & how to apply it when you need it
That was very interesting. Amazed how much torque the sacrificial candidate could take. I'd be interested to see other demonstrator pens examined and compared.
I had to call it quits on breaking the pen. I was putting so much energy into the pen I was worried how big of a BOOM would result. I didnt have glasses on and would be a total idiot if I took one to the eye from doing this test LOL
I have the cheap pen there and it's a surprisingly nice writer. A buddy of mine's wife had her Eco crack and TWISBI replaced it with another Eco that cracked. But another friend has 10 Eco pens that he uses for drawing and has had no issues. I've got two and no issues with mine either.
I have three Ecos and one of them developed a crack near the feed. The pen that cracked was one that sat on my desk and wasn’t used very often so how that happened is beyond me. It cracked 30 days after I got it.
I have heard of a lot many cases where TWSBIs which sat unused cracked but the ones used regularly did not. As seen in this video, putting stresses on the section changed the stress map of the area. May be it is the case that pens that are used often go through such stresses in regular use that alters their stress map in a way that reduces the chances of breaking.? I am purely speculating, and linking my observation to such speculation.
Wow. TWSBI has a problem. So where I thought the Eco would not have the same cracking issues as the others, my Eco is now on it's second replacement for cracking in the section near the feed. I used the pen a lot, because it was one of my ink testing pens.
@@Ambicrush I have two others and one gets used even less and one gets used more. The only difference is when I got them. The two that haven’t cracked I got at the same time. The one that did crack, I got later. Although it would be nice to know why some crack and some don’t, there is a problem and I shouldn’t have to work around it.
Doesn't this apply to all plastic fps with friction fit nibs? The Pilot 823, I believe, has such a nib...now I understand why Pilot issues warnings telling customers not to take apart the pen.
Plastics are NOTORIOUS for poor temperature tolerances in manufacture... This is what makes recycling them (and repurposing on your own) a damnably dubious operation. The TWSBY Eco is an economically priced pen, so chances are they're just furiously being pounded out in the factories... From personal experience, I know there are times of day, work-cycles, and production situations where the molds and machines might not be as hot as they quite should be... OR there's a "pre-heat" duty cycle involved, and sometimes that can get done "impatiently"... As you pointed out in the vid', "When you put out big numbers, even a 1% failure rate can be a big number." SO most modern productions DO try for a 99.9% precision and consistency. Many actively try for more... BUT even that 0.1% gives a solid average 1 out of every 1000 pens is going to fail... At 10,000 units a month (mid-range decent output from modern factories on something so easily stamped out) that's at least 10 pens a month "gone bad"... for whatever reason... AND even a once a month clean out or maintenance cycle could explain the temperature related reasons why... BUT it comes down to plastic's (ANY Plastic) cooling rates... If they cool too slowly, they stay soft too long and deform. If they cool too quickly, you over-stress the plastic, by much the same principles as tempering glass or steel. A "Prince Rupert's Drop" in glass (if you care to look it up) explains how the outermost layer cools faster than inside, and adds to stresses as it contracts... Steel is Iron with Carbon added, and from a particular temperature to properly combine the two elements, it's got to be cooled at a very specific rate to another very specific temperature (which ordinary oil does surprisingly well at an appropriate temperature) to CRYSTALIZE the bond structures between iron and carbon and harden or "temper" the steel... I'm no expert. I know somewhere between those two principles, you'll likely figure out what's going on with the plastic... BUT if an optimally produced pen has those stress lines consistently in that place near the tip, I'd suggest a slightly improperly cooled pen would only grow them to some catastrophic length/size and direction... AND even regular use can create problems... Higher-end makes of pen charge more for materials, EVEN if they're the same materials... This is because they can take the option of producing virtually the same part in the same way, except they already know about the stress-points at the end... AND they just add about an extra quarter inch or so (roughly 6 mm) that can then be ground or cut off gently (so not to add stresses) to get rid of the worst failure points rather than risk it... What I puzzle over... however... is whether one could feasibly just re-heat and cool the plastic to "relax" those stress points... We CAN search up the plasticity temperature for ABS, and the optimal cooling rate... AND I doubt we'd have to fully reach even deformation before it starts relaxing... AND then just slow down how quickly it's allowed to cool back to room temperature... I know your "higher-end pen" was a completely different material in this example. I'm just pointing out one of the "easiest" options for fixing the issue, and how it would potentially look... I love this kind of thing... haha... Tinker. ;o)
Have three ecos. First one developed a crack right below where the feed/nib opening is. They sent a replacement. Few months go by, crack develops. Bought two more and both those developed cracks in the same places.
Very cool. I have several TWSBI Ecos and I haven't experienced any cracks. If I have an issue and end up pulling the nib/feed I'll know what to look for.
The Ecos crack mostly on the edge of the body around the feed. The reason is as you cap the pen it pushes the body of the pen into the plastic inner cap. Repeat this process a couple dozen or hundred times and add in the brittle plastic TWSBI uses, you get cracks. It isn’t rocket science, it’s both a design and material flaw. TWSBI needs to change the plastic it uses or add metal to the section . I’ve noticed far less complaints of the 580 cracking in that spot. And the 580 has a metal there that contacts with the inner cap, rather than plastic. Instead the 580s crack where the nib until screws into the body of the pen along the threads. Call it over tightening but repeated stress on these parts (over time) will cause cracking.
We can't be certain that is the issue. People have reported cracking after only a few days of use. And have even had the issue happen almost immediately after installing a replacement barrel. I'd have to get my hands on a brand new Eco and do a stress map to check it. The nature of the pattern leans me towards there being an issue during the injection process (there are many variables and a slight discrepancy in heat anywhere along the line can cause these issues) or in the finer details of the design near the end of the section. It could be the changes in material thickness or radius of contours are too much over such a small area and is inducing internal stress concentrations when the part is formed. Could even be in the post processing. The excess material has to be removed and could be as simple as the cutting process which trims the parts can be inducing stress points. This would be the type of project I'd love to work on as I'm used to do this type of work in the past. Hunting down some obscure problem is my kind of jam. To do this one however, I'd have to actually be at the manufacturing facility inspecting the entire process and inspect and log parts after every single step to find the issue(s). Could easily take a few months to track it down.
I have a TWSBI Eco from bleskit, and after using it a lot I've come to realize that people are just screwing the cap on too tight. There's no thread lock so you can just keep going until it cracks
Its most likely an accumulation of multiple factors vs just one. The lack of a hard stop to prevent over tightening is just one more thing that can cause issues
Yes. Mine too. Within one year I had a ~3mm crack, and then a couple days later ~1.5cm crack. Also noticed a small crack in the cap. TWSBI covered it. I recently received my second replacement because of the same issue. Meh, I have move beyond TWSBI now.
It's a phenomenal book! That was my Christmas gift my wife "got me". Wife: What can I get you? Me: There's this engineering book I want to nerd out on Wife: Done! Order it! Me: 😁😁😁 Super cool I got Dan Gelbart to sign it when he had me over at his house.
I have 12 TWSBI pens and 12 Lanbitou 3059s. It has been over 5 yrs and I have had no cracking with the TWSBI pens. The Lanbitou 3059, the knockoff of the TWSBI, has had no cracking issues with them either. It appears from your demo that it takes a lot of torque/mistreatment to cause cracking issues.
Hey DB. If you put a polarizer filter on you camera, this will work much better. Just turn the filter on the camera lenses until the background (laptop screen) goes black. And any transparent object you view in between will be ultra high def to show the stress within the plastic.
I was going to order some proper filter material to do just that, but opted for the method where everyone can do this at home. I always enjoy finding the most basic & simple way to do something. Makes the challenge even more fun. But I'll probably order some proper filter material at some point. Also did it this way so when I get requests in comments for me to check this or that I can say "pull out your sunglass and give it try for yourself, only take 2 minutes 😁"
Unfortunately both of mine are cracked. Right at the end of the barrel right where the pressure spots are. I wonder if I was twisting the lid on too hard and not realising it.
What's the glass transition (or is it just melting?) temperature of this material? (polycarb?) I have a heat gun that can go up to about 350c, so I would be curious if it would be possible to anneal the problem area to at least reduce the stress.
I don't think the eco is made from polycarbonate. Polycarb is very good for impact resistance so don't think the cracking issue would creep up. I believe it is made from some type of Acrylic (PMMA)
@@Doodlebud That is odd, Jetpens says that the body is made out of "plastic," which is often differentiated from acrylic. I do find it annoying that they don't say the materials on the official site however. Thank you for the starting point however. Regardless, I ordered one and, I'll be getting it in on like the 3'rd, so I'll look it over and see what I can do. Fakeedit: I looked it up and acrylics are technically plastics. Never thought of that, but it makes sense. Regardless, PMMA has a melting temp of 160c, so I may attempt something, hopefully without destroying the pen. (worse comes to worst, I just don't bother, wait and see if it cracks, and if it does just do remelt with some clay. Not like I can make it worse.) Thank you again for the info.
Yeah the term "plastic" drives me nuts. It like saying something is made of "metal" and not differentiating what type of metal. When someone says "oh it's just made of plastic..." it let's me know they have no idea what it's made of 🤣
My 580 alr cap and clip just broke last week. It was in a pen tray. It wasn't even taken out. It had cracked when it was inside the tray. How is that even possible? The pen had been there for atleast a month.
It could have been contaminated. There are some chemicals that react with acrylic. Even something as simple as certain hand creams etc can have stuff inside that can cause damage. And all those need are time to let the reaction take place. For example I've seen parts fail in the field because loctite was applied to screws that come in contact with certain plastics and caused complete failures in parts.
Just spitballing here, but when I used to do a lot of laser cutting of certain plastics (specifically cast acrylics), the high stress areas, when contacted with isopropyl alcohol would turn into some serious cracks. Could those who experienced these cracks be trying to clean their pen with an alcohol pad or something?
Alcohol will for sure cause cracking, but I know people who've had their crack and they do not use any alcohol when cleaning their pens. In some cases there are reports of pens cracking just a few days after receiving a new pen and it hasn't been filled with anything other than ink.
At least we know that the Chinese test pen (I guess it's a Lanbitou) won't crack under this severe (torque) test. I really doubt that the ECO could stand this test - I would bet some serious money that it would have cracked way earlier! (Idea: ask 60 followers to send you 50 cents so you can do the TWSBI Crack Test 😂). Had you done this video two weeks earlier I could send you the shot of my 580 cracked cap (right above the cap band). Really enjoyed this video ! Thanks 😊
Parkers has the most durable body......Hope you do reveal why the Mont Blanc n Pelican cracks on its own ...in the shelves at room temperature for a pen which is valued more then gold . The world would appreciate your reviews. Tq so much.
I’ve had my eco for about a year. Last week i noticed hairline cracks in the grip section close to the nib. I’ve never disassembled it, dropped it or overtightened the cap.. I’ve enjoyed using this pen a lot for drawing, but I doubt I will purchase another because of this issue.
Hi DB, at about 2:00, your book, chapter 2.3.9., suggests to anneal the component for releasing the stresses. I have no idea at what temperature that would be for this plastic. Chances might be high that deformation might happen very close to the required annealing temperature and the cooling should probably happen infinitely slow. But isn’t it worth a shot? You could anneal the cheap pen you didn’t manage to break... 😅. Looking forward to your results.
Pardon my francais; you're videos are f'inkg awesome! Finally, now I know it's not my fault. I recently got my replacement barrel for my replacement barrel for my Eco. I'd heard about cracking issues, but TWSBI made a point that they fixed everything for the Eco. And both times the Eco cracked at where you those stress points are. You did it with just those pieces of equip., and TWSBI couldn't do that. Shame. From now on, I don't think I am pulling the feed on friction fit, unless the casing looks study. Thanks for the info and video.
@@Doodlebud What if I ran the nib and feed and the section part under cold water? Would that help in anyway to prevent expansion of the parts and therefore stress and cracking?
@@Doodlebud What about a fluid dynamic issue. Perhaps it just needs some hydraulic fluid to help strengthen the plastic. Okay, I don't know what I am talking about. I just wanted to sound as smart as you.
Wow. I was gonna buy an Eco but after reading about all these cracking problems, I think I'll just stick with my Lamy Safari for drawing. I have a Pelikan M205 I use for drawing but I found out Pelikan doesn't sell any aftermarket nibs so it's not something I can but through a retailer...which sucks. At least I can buy a Lamy nib for $16 and I am drawing again.
The vac filler might be better, since they have to be made to more precise spec for the vac filling to work well, so perhaps that means the rest of the body is also more precise dimensioned. Also with the soft plastic between the pen body and feed it would avoid putting extra stresses on the end section during cleaning as that insert soaks up some of the rough handling.
I've had a vac mini for a few years and it was fine. Then, all of a sudden, hair line cracks around everything with a hard edge. Where the back screws in, edges of the cap, the section attachment point, etc. And I know it wasn't a hand sanitizer situation as it was only getting used at home at that point. REALLY weird.
@@Jarrych83 Ah, the mystery of the TWISBY crack strikes again. I hear so many of these at this point that I wouldn't buy any of their hard clear resin pens. The GO is safe as it uses softer plastic where it counts, although it does look like the cheap pen it is. Swipe might be also OK on this count, but that useless clip is just a nope for me.
@@martinlebl631 It's very frustrating. I do need to message TWSBI and see if they'll do anything. Lovely pen and a phenomenal size and shape for daily carry. But it's tough at that price when you're worried about the durability.
I think if you don't handle the feed, and don't get a bad batch it is likely fine. I think the injection molding may go out of spec over time, and if no one notices soon enough you might have few thousand less than perfect pens go out that are prone to cracking. If no one notices, and it is brought back into spec by some routine maintenance, then it might be pretty hard to trace it. Which would explain why they haven't kicked it yet. The fact that they have a ready supply of replacement parts as an established program speaks volumes about the size of this problem.
I read sometime back that TWSBI made some changes to the ECO to address the cracking problem. I don’t know what those changes were, but I suspect they were formulation changes to the plastic. Maybe thickness changes around the nib end. Regardless, the TWSBI plastic is quite brittle. If you had jammed that screwdriver into one of your ECO’s I bet it would have cracked with very little moment stress. That’s my theory anyway, based on personal experience. Nice vid, as always!
I've had 3 ecos and a 580AL crack. Most of my pens have been fine, but the older ones in particular seem prone to the issue. It really does seem to be a luck of the draw sort of thing. There's a selection bias in crack complaints. people know TWSBIs crack so if they spot one, they're more likely to gripe about it.
3 twsbi pens.. 4 cracks.. broken bodies.. caps. sections.. that material is brittle and develops lots of hairline cracks which build up. the cheap pen looks like it uses a softer plastic, which may be why it holds up well.
Would a lighter’s flame reset the stress point in the plastic? Or would that make it worse? I have a TWSBI Go which happens to be my oldest pen and it’s also my work pen, so it takes a beating. No cracks. I’ve gone through two TWSBI Ecos. One cracked falling from pocket height onto carpet. And the other fell from shoulder height onto tile. If I ever buy another TWSBI, I’ll stick with the Go. It’s hella cheaper and I like one handed refilling. I don’t want to buy any of their more expensive pens because of cracking. Wish TWSBI didn’t make solely demonstrator pens.
Well TWSBI does make non demonstrator pens. Precision, Classic and Draco, are either metal or opaque plastic pens. I think Go is made from different and softer material than ECO and Diamond models.
@@korax67 Yep, feels like you could gauge it with your fingernails, but I don't think it will crack. And it is cheap enough that if you use the nib elsewhere after it fails it is still worth it.
They just sell millions of the TWSBI Eco, so even with a failure rate of 0.1 % every one million pens sold 1000 people end up with a broken pen. And I don't know the sales numbers but I know that this pen is very popular and most people don't only own one of them ^^
Very cool stuff!! It would be nice to have a way to "see" the stress in non-demonstrators too. For me, the Eco piston function didn't work and would unwind itself after filling. No cracks as of yet, just useless in another manner.
We don't know for sure if thats the issue. There are endless variables in tracking down the real source of this problem. This type of thing could easily take months for someone to track down specifically working on this type issue (I've done stuff like this in the past). Some people have reported the pen cracking almost immediately. I'm more leaning towards an issue during the injection molding process (most likely heat profile) or post processing. The heating/cooling profile is the major cause of internal stresses for these types of parts. It can also be in tiny features in the design of the pen. The stress map shows its concentrated at the end of the section and only comes down about 2-3mm into the section. It could be the change in contours at that region without the correct material thickness or supports can cause hot spots in the stress map. Large profile changes over small distances are common stress points.
@@Doodlebud Doing injection molding well is harder than people realize. And any corners you cut, or the press, or cooling lines going out of spec is going to have consequences that might not be immediately apparent. My theory is: (1) something goes out if spec, (2) molding makes problematic pen bodies which go out into the wild, (3) no one notices this problem, (4) it is brought back into spec by routine maintenance performed as schedule. Now when the cracking is reported in the wild, it is very hard to trace the cause.
In non transparent materials you could use infrared/thermal imaging, or x-ray imaging to observe the stresses, but that isn't quite so easy to improvise from items you have on hand, unless you have some mad scientist lab in the basement.
could they be more prone to cracks due to climate even moreso than reoccuring stress? From what ive noticed, people who had one cracked eco/vac/580 seemed to live in colder climates
Mine was fine until I dropped it three feet onto a concrete floor. I emailed TWSBI and they're sending me a new section/barrel. Once I get it I'll keep the same nib in there and likely not travel with it... Too fragile.
I would have thought that the contours show the variation in stress. So, you could have a pen that is uniformly highly stressed and shows no variation... Which could be as likely to crack as one showing variation (lots of contours)? Also, I should think that different materials will refract light differently under different ranges of stress, so comparing different pens (plastics) would be difficult. Finally, there's the difference between hard (brittle) and (soft) tough materials. So, whilst we may not want our pens to crack, we also would like the "quality" feel of harder plastics. I can see a lot more experimentation here, crushing various pens and measuring the load and displacement!!
The first question about stresses is far to long for me to give input in the comments. But if you want to learn more read up on "photoelasticity stress analysis" and that will fill you in
Part of the reason that the only TWISBY I own is a GO, as that is a pretty soft plastic that wouldn't be prone to cracking, and would likely stretch first. Of course it doesn't look pretty, and is very much on the functiona side of things.
I had 2 twsbi pens, 580 and vac mini, both had cracked in different places, for both , I got replacement part from twsbi, later both pens again cracked in different places, I just gave up, savaged the nibs and throw the pens in frustration, never going to buy twsbi again.
I bought a beautiful and nice 580 with a stub 1,1mm nib but destroyed it just one month after buying it because of ink in poor condition..smelled like ammonia but I noticed it too late..
I have a lot of Twsbi's -- The only problem I had is when I acidently spilled alchol on a cap, and it basically ate it. Twsbi sent me another cap. Also, I lost the o ring from the orginal Vac 700 and they sent me a new one.
@@Doodlebud Their Customer Service is wonderful. To anyone who has a crack in their Twsbi's I would strongly recommend to contact Customer Service to get a replacement part. Their Customer Service is the reason why I will keep buying Twsbi's. But I haven't experience a crack in any one of my over 30 Twsbi's I have. Not to say it doesn't happen, I just haven't experienced it.
Lol, this video was cute, but the reason why the Eco's are cracking isn't because of "stresses" placed on it as force. It's the material that it's made out of, any alcohol or ethanol interacts with the acrylic it's made with. I discovered this after some research when my pens were cracking. I would clean them with an alcohol mixture, and cracks would start to form the next day. Some inks have low amounts of alcohol in them or ethanols for various reasons and their recipes are mostly secret anyway, but the low levels of any of these chemicals will slowly start to crack the acrylic. I was cleaning my pens with 70% rubbing alcohol and they would crack the next day. Brand new pens too.
I'm very aware alcohol makes acrylics crack. But claiming that the only reason a pen cracks is from exposure to alcohol is a giant assumption. People have reported cracks from using it only a couple of times. And this is well before Covid with everyone using hand sanitizer. I'm not claiming that the stress points are the reason either. But the reported cracks align where these internal stresses concentratios are seen. Photoelasticity is a very common way to inspect parts for these exact types of issues. The truth is none of use know the exact cause of the issue. Also it is advised to never use alcohol when cleaning pens, so that's not a good idea to begin with.
@@Doodlebud I actually spoke to the rep at TWSBI when I was reordering them and describing my issue. They were the ones who told me that ethanol will crack it. He says majority of cases are from manufacturers that use some form of ethanol in their inks or someone cleaning their pen with it.
@@Doodlebud What can cause acrylic to crack? When acrylics come into direct or indirect contact with harsh solvents, the liquid or fumes may cause a drying effect that stresses the material to the point where it becomes brittle and suddenly cracks and/or crazes. This is due to a chemical reaction occurring between the solvent and the acrylic.
@@Doodlebud Something as innocuous as cologne can cause this. There are a myriad of things in households and around us that would cause these cracks. Sometimes it may just hairline crack it and the act of writing would put enough pressure to stress the crack further.
@@Doodlebud retire professor of applied mathematics (Georgia Tech) Graduate degree is from Carnegie-Mellon, where I had several courses on continuum mechanics.
No any more, I'm now a financial planner. But used to work in precision laser measurement equipment. All the way from R&D, design, manufacturing, assembly, test, install, & support. I bring up some things from that world to talking about fountain pens oddly enough 😆
As much as I thought my money would be going to a new pen sometime in the future, now I'm super excited to get that book Building Scientific Apparatus XD Lol. Hmmm, I'll first see if my library has a copy I can borrow cause. I'm sure that's gotta cost some big bucks. 😅
Quick note on "using your phone screen" - AMOLED phones won't work, they have to be LCD. A lot of modern phones are AMOLED these days, and they do not produce polarized light.
Perhaps your 'sacrificial' pen is made from a different plastic or plastic mix to the TWSBI - one that is actually tougher?? In my experience TWSBI pens are a brittle sort of plastic. I doubt any would have survived the treatment you gave the poor sacrificial one! I was put off TWSBI years ago because of cracking issues I had. I am amazed that all these years later the issues clearly have not been resolved. Until they are I wouldn't buy a TWSBI.
Yeah...its that kind of plastic that has the potential to crack that I don't like with the ecos..they are great pens...but if it cracks..goodbye dry out protection.
Very informational video again! I will try to do the same at home to see the stress pattern around the cracks in my two cracked TWSBI ECOs. A scientific minded TH-camr like you is exactly what the fountain pen community needs to help objectify things. On a separate note, I can't believe that a big guy like you couldn't break that cheap little pen! Lol, JK :)
Best comment so far! "I will try to do the same at home...." Lots of folks giving conclusions, but few saying "I have an idea of what it could be, let me do some tests and see." That pen is a tough little F**ker! LOL I could have gone harder but I was started worrying about the amount of energy I was putting into the pen and was very aware its going to release at some point and go BOOM!
@@Doodlebud Exactly! Almost all pen reviewers just give their opinion on pens which will almost always be biased. Your videos, because of their scientific basis benefit everyone equally🙏
I wasn't really talking about reviewers, it was more folks on forums, comments, etc. It amazes me how the work between hypothesis and conclusion seems to vanish. "Here's what I think is going on..... therefore that's what's going on"
@@Doodlebud It might be that the cheaper knockoff is made out of cheaper softer plastic, which doesn't look as shiny, and scratches more easily, but is also more pliable, so it bends instead if cracking, while the harder shinnier plastic of the ECO cracks as it cannot give. Perhaps comparative screwdriver test, a la Project Farm could settle that.
Interesting analysis, just don't stress your pen in front of your laptop screen with a screw driver. You run the risk of slipping, and smashing the pen + screwdriver through the screen.
That's why I called it quits. There was so much energy going into the pen it was going to get released at some point in a very rapid way. Either big BOOM or hand slips and no my laptop is a custom screwdriver holder
They are made from different plastics so they have different properties. The build quality on the knock off is terrible, but the plastic is more flexible
Sorry, but the nominative plural of “apparatus” is not “apparati,” but “apparatūs,” with a long “u” in the last syllable. Although “apparatus” may look like a second-declension noun, it is in fact fourth declension, like “genus” and “spiritus.” For those of us who wasted our time getting a Classical education, Latin is not yet dead enough that its grammar ought to be completely ignored.
In a fit of frustration, I threw out my three TWSBI Vac-700s. I saved the nibs. I bought all three pens about 6 years ago, in 2016. In all three cases, the section literally cracked and broke near the bottom. So it's impossible to fix. An analogy would be a broken light but with the base still screwed in. TWSBI should be ashamed of its quality control. There is none. Google and ye shall fined hundreds--literally hundreds--of complaints regarding cracked TWSBIs. In my case, the nature of the failure rendered the pen impossible or uneconomical to fix. So, to part ways with the company, I tossed their products where they belong: in the dustbin of my history.
I can't believe I found a physics and pens TH-cam channel. That's a super cool inspection method!
Something simple anyone can do at home too. You might like this video which takes the same approach for another topic 🤓
th-cam.com/video/SzYkIhuDDcc/w-d-xo.html
The much maligned and disrespected "cheap knock-off" displayed a feat of supernatural toughness, strength. Even brutal torture could not break its resolve. Applause for the underdog. Thanks for the demo on materials science. I'm always enjoy learning something new from your videos.
I was waiting to see if it still worked.
@@d077Z That would be a real kick in the shins for the ECO, so it probably does.
Half of my TWSBIs are cracked. His customer service has been amazing, but I simply cannot count on these pens in daily use. Thanks for this video!!!
you still pay for shipping...
@@Cortesevasive Decent customer service for sure. Not free, but convenient. The fact that the program is so well known and well established means they ship a lot if these. (If it was very rare, then they could just eat the shipping on those rare occasions.)
After 7yrs of regular use, one of my 3 ECOs developed a hairline crack in the section. $5 got me a new pen body. I've wondered if new hobbiests are applying too much pressure on the nib, which in turn is adding significant stresses to the section. That and the fact that the ECO has become a phenom in terms of units sold (so we hear about a lot more cracks because they're selling a ton more pens). Dunno for sure, and back when the ECO first launched, there were a lot of reports that the cracking was due to stress introduced by the manufacturing process. Thanks very much for sharing the video. Nice work!
I have 3 ECO’s, and they all was cracking after 3 month
I once had a project where I had to write a cleaning specification for cast acrylic slabs 10 feet long, 5 feet wide and five inches thick. In researching compatible solvents / claening materials for these slabs, I was shocked at the high number of organic solvents and cleaning compounds that will attack acrylic. The primary indication of chemical attack is crazing / cracking at stress concentration areas and where internal stresses are high. The only cleaner I could suggest was a mild dish detergent and soft water.
I'm not certain, but there may be certain additives in some inks that attack some acrylics used for pen bodies. Inks can contain surfactants, viscosity modifiers, preservatives, scents and perhaps other propriety ingredients that alone, or in combination may be incompatible with pen bodies in acrylic.
Yup, plenty of everyday stuff can attack acrylics and can be found in very unsuspecting places.
Or in the pen flush people use in between ink fills.
Great comment, Ty!
My first three pens I bought about four years ago now were a Pilot metropolitan, TWSBI GO, and TWSBI ECO. I was new to pens and wanted to use them at work. I work at a fast paced environment, capping and uncapping my pen hundreds of times in a day and setting it down not so carefully on a hard counter. I dropped my metro and busted the nib (oops but not a great loss to me honestly) and my ECO DID develop a hairline crack right where you pointed out on your video after I had taken the nib and feed out to clean it. I still use it often since it really hasn’t affected it, albeit a little more carefully. My GO is GOing strong and I still use it daily at work without any cracks or problems. It’s my daily “chuck it around” carry. I have since bought two ECOs and haven’t had any problems at all, likely because I have no need to remove the nibs and have treated them nicer than the me of four years ago. That has been my limited experience! I think had I had less micro impacts from setting my TWSBI down in a rush all day and had I not removed the nib, I wouldn’t have had a crack.
The two TWSBI pens I have had crack were the original limited eco they did in the turquoise, and the vac 700R iris. On the eco it is around the collar where you observed the pressure points on yours, and I never removed the nib. It was from the pressure of writing. That pen isn't with me right now, but I have in my hands the cracked vac 700 Iris, where the cracks are on the cap threads, on the end where the whole nib unit screws into the barrel, but the vac 700 cap is cushioned in a way the eco isn't. I emptied that pen twice before they showed up. I have a replacement barrel now, that I have been waiting for the third fill to get used to replace it. In both cases the cracks are vertical, which suggests to me they are from lateral pressure and not torsion, but maybe with how small the cracks are the two would present the same way. Part of the issue is going to be what TWSBI is using for the material. In order to make it crystal clear, it's inflexible, unlike the chinese pen. It's very brittle. The rest of my Ecos were fine before I sold them on (the japan exclusive orange, china exclusive pink and blue, a couple other limited ecos and two eco-t's - for awhile I was collecting every solid color they made as it came out), and I've never had any of their other pens. And I think you actually hear about it happening _less_ than it actually does, because of TWSBI's replacement policy. The pens aren't going to go back to a retailer, and TWSBI has no incentive to release real failure rates when they can just say, "Fake news." I think that you are probably right about the overall failure rate being low, but considering the sheer volume of production TWSBI does, that can still be a large number of pens. Say they have produced a million pens across all of their product lines over the past ten years and the failure rate is 1% - thats still _thousands_ of pens that fail.
Very informative, thanks. I have two TWSBI Ecos (one , one ) - I really love their capacity, looks, and nibs . I've had both pens for about 2 years, they rarely leave home and I treat all of my things with care. Yet both of them developed cracks at the top of the section near where the nib enters the pen, just like you showed, which is very disappointing as I consider them some of my favorite pens. I never pulled the nib/feed out of the pen for cleaning, so that's not it.
Maybe the factory fit the nib and feet too tight, and over time some cracks formed? Just a guess
@@TheCreedBratton Yes, could be -- too bad though.
@@levon9 some of my pens have had super duper tight feeds from the factory. There is no need for it. In fact, just removing the feed risks damaging it sometimes when it is that tight
@@TheCreedBratton Good point. I've read about people damaging the fins on the TWSBI feeds while trying to yank them out.
"Terrible Pen Is Unbreakable!"
Thanks for the pretty light show.
It didn't work very well, cap has rust from the screw, threads were chewy, brush unit would almost fall out from the of the body it was so loose, and the piston action was terrible.... but the little f**cker can take a BEATING!
@@Doodlebud Which it deserved for being a terrible pen.
Between 2017 and 2018 I had 4 TWSBI Ecos, from 4 different online vendors - 3 developed cracks in the section. The first 2 I used heavily for writing notes and drawing ( I use my pens primarily for art), the last 2 I babied alot but #3 still developed a crack so I sold off #4.
Afterwards I used alot of cheap wingsung pens (3009, 3008, 3003) and they held up way longer than the Ecos - and I wasn't as careful with them cause I figured they would break but at least they are only $5 each instead of $30.
With the TWSBI, I agree that it is/was a tolerance problem with the opening being too small for the friction fit nib and feed, but the whole experience soured me on the pen. It's possible they did improve the resin but who knows when the "bad batch" was and how much old stock still remains. That is probably why it still is being reported regularly - they didn't do a recall but they just send you a new (hopefully improved) barrel for the cost of shipping.
Yep. I am recently on my second replacement because of the same issue; cracks in the section lip. So I thought I might have been too rough taking the feed out and putting it back in. Now I know it's not my fault. Just as you, I am off TWSBI.
Love watching you science the heck out of a pen person’s eternal questions! Another aspect I wonder about: vulnerability of various plastics to chemical residues on our fingers, particularly ethyl alcohol. The cap of a TWSBI Classic I have (different type of plastic) completely disintegrated on me a few years ago; I realized it may have had to do with a brief Purell exposure (and Philip of TWSBI confirmed that this could be an issue). So I wonder about the section of the pen, and exposure to still-moist, ‘decontaminated’ "fingers. Clearly, this is not the sole cause. (I’m also recalling Waskisquirrel’s beloved Pilot Custom 823, whose barrel became completely crazed through exposure to a household cleaning liquid.)
Yeah other chemicals reacting is definitely a possibility. I'm leaning towards stresses during the manufacturing stage somewhere along the line. There's so many variables to pin down but this would be a project if love to do. My favorite thing to do was track down a problem or solution, especially when it was strange & obscure. Spent a week tracking down an issue with a precision motion system and it turned out to be caused by a slight deviation in the finish on a pair of stainless steel guide shafts. I love the creative part of the problem solving process. Keeps it fun
This video is the pinnacle of DIY analysis on TWS... Fountain pen cracking!
Can't believe I forgot about this method for so long and it was finally my wife's cracked tooth that reminded me! There is proper gear I could have ordered to make this a better setup but I did it this way so almost anyone can do this themselves.
I came back because I forgot to give you a thumbs up for using bifringence to visualize those internal stresses. It's wonderful to see the vast reaches of techniques I saw in school used to answer relevant questions surrounding our inky hobby. 👍😁
Yuppers, just have to remember all that stuff which is the hardest part. There's so much info out there it's tough to remember it all & how to apply it when you need it
That was very interesting. Amazed how much torque the sacrificial candidate could take. I'd be interested to see other demonstrator pens examined and compared.
I had to call it quits on breaking the pen. I was putting so much energy into the pen I was worried how big of a BOOM would result. I didnt have glasses on and would be a total idiot if I took one to the eye from doing this test LOL
@@Doodlebud No, you took it further than I would have. Good sense to call it off before failure. We still learned 'stuff'.
@@Doodlebud Also leaves some content for the follow up video.
I have the cheap pen there and it's a surprisingly nice writer. A buddy of mine's wife had her Eco crack and TWISBI replaced it with another Eco that cracked. But another friend has 10 Eco pens that he uses for drawing and has had no issues. I've got two and no issues with mine either.
I have three Ecos and one of them developed a crack near the feed. The pen that cracked was one that sat on my desk and wasn’t used very often so how that happened is beyond me. It cracked 30 days after I got it.
Same for me.
I have heard of a lot many cases where TWSBIs which sat unused cracked but the ones used regularly did not. As seen in this video, putting stresses on the section changed the stress map of the area. May be it is the case that pens that are used often go through such stresses in regular use that alters their stress map in a way that reduces the chances of breaking.? I am purely speculating, and linking my observation to such speculation.
Wow. TWSBI has a problem. So where I thought the Eco would not have the same cracking issues as the others, my Eco is now on it's second replacement for cracking in the section near the feed. I used the pen a lot, because it was one of my ink testing pens.
@@Ambicrush I have two others and one gets used even less and one gets used more. The only difference is when I got them. The two that haven’t cracked I got at the same time. The one that did crack, I got later. Although it would be nice to know why some crack and some don’t, there is a problem and I shouldn’t have to work around it.
@@MrEdIsTheSource i agree, and i feel that the best customer service is one which doesn't have to do any customer service.
Doesn't this apply to all plastic fps with friction fit nibs? The Pilot 823, I believe, has such a nib...now I understand why Pilot issues warnings telling customers not to take apart the pen.
Yes it does
@@Doodlebud you answered before I editored...arrgh!😂
Wonderful how you combine science and fountain pens. Thank you for what you do sir.
These are just things I enjoy doing and how I think. I'm glad other people enjoy how I look at things and my approach
@@Doodlebud love your approach sir. Excellent science communication!
Plastics are NOTORIOUS for poor temperature tolerances in manufacture... This is what makes recycling them (and repurposing on your own) a damnably dubious operation. The TWSBY Eco is an economically priced pen, so chances are they're just furiously being pounded out in the factories... From personal experience, I know there are times of day, work-cycles, and production situations where the molds and machines might not be as hot as they quite should be... OR there's a "pre-heat" duty cycle involved, and sometimes that can get done "impatiently"...
As you pointed out in the vid', "When you put out big numbers, even a 1% failure rate can be a big number."
SO most modern productions DO try for a 99.9% precision and consistency. Many actively try for more... BUT even that 0.1% gives a solid average 1 out of every 1000 pens is going to fail... At 10,000 units a month (mid-range decent output from modern factories on something so easily stamped out) that's at least 10 pens a month "gone bad"... for whatever reason... AND even a once a month clean out or maintenance cycle could explain the temperature related reasons why...
BUT it comes down to plastic's (ANY Plastic) cooling rates... If they cool too slowly, they stay soft too long and deform. If they cool too quickly, you over-stress the plastic, by much the same principles as tempering glass or steel.
A "Prince Rupert's Drop" in glass (if you care to look it up) explains how the outermost layer cools faster than inside, and adds to stresses as it contracts...
Steel is Iron with Carbon added, and from a particular temperature to properly combine the two elements, it's got to be cooled at a very specific rate to another very specific temperature (which ordinary oil does surprisingly well at an appropriate temperature) to CRYSTALIZE the bond structures between iron and carbon and harden or "temper" the steel...
I'm no expert. I know somewhere between those two principles, you'll likely figure out what's going on with the plastic... BUT if an optimally produced pen has those stress lines consistently in that place near the tip, I'd suggest a slightly improperly cooled pen would only grow them to some catastrophic length/size and direction... AND even regular use can create problems...
Higher-end makes of pen charge more for materials, EVEN if they're the same materials... This is because they can take the option of producing virtually the same part in the same way, except they already know about the stress-points at the end... AND they just add about an extra quarter inch or so (roughly 6 mm) that can then be ground or cut off gently (so not to add stresses) to get rid of the worst failure points rather than risk it...
What I puzzle over... however... is whether one could feasibly just re-heat and cool the plastic to "relax" those stress points... We CAN search up the plasticity temperature for ABS, and the optimal cooling rate... AND I doubt we'd have to fully reach even deformation before it starts relaxing... AND then just slow down how quickly it's allowed to cool back to room temperature...
I know your "higher-end pen" was a completely different material in this example. I'm just pointing out one of the "easiest" options for fixing the issue, and how it would potentially look... I love this kind of thing... haha... Tinker. ;o)
Have three ecos. First one developed a crack right below where the feed/nib opening is. They sent a replacement. Few months go by, crack develops. Bought two more and both those developed cracks in the same places.
Wow that's crazy
@@Doodlebud agreed because I love the pens.
Very cool. I have several TWSBI Ecos and I haven't experienced any cracks. If I have an issue and end up pulling the nib/feed I'll know what to look for.
that is an amazing video ! And I did not know the wonderfull book you showed at the beginning ! Thanks a lot !
The Ecos crack mostly on the edge of the body around the feed. The reason is as you cap the pen it pushes the body of the pen into the plastic inner cap. Repeat this process a couple dozen or hundred times and add in the brittle plastic TWSBI uses, you get cracks. It isn’t rocket science, it’s both a design and material flaw. TWSBI needs to change the plastic it uses or add metal to the section .
I’ve noticed far less complaints of the 580 cracking in that spot. And the 580 has a metal there that contacts with the inner cap, rather than plastic. Instead the 580s crack where the nib until screws into the body of the pen along the threads. Call it over tightening but repeated stress on these parts (over time) will cause cracking.
We can't be certain that is the issue. People have reported cracking after only a few days of use. And have even had the issue happen almost immediately after installing a replacement barrel. I'd have to get my hands on a brand new Eco and do a stress map to check it. The nature of the pattern leans me towards there being an issue during the injection process (there are many variables and a slight discrepancy in heat anywhere along the line can cause these issues) or in the finer details of the design near the end of the section. It could be the changes in material thickness or radius of contours are too much over such a small area and is inducing internal stress concentrations when the part is formed. Could even be in the post processing. The excess material has to be removed and could be as simple as the cutting process which trims the parts can be inducing stress points. This would be the type of project I'd love to work on as I'm used to do this type of work in the past. Hunting down some obscure problem is my kind of jam. To do this one however, I'd have to actually be at the manufacturing facility inspecting the entire process and inspect and log parts after every single step to find the issue(s). Could easily take a few months to track it down.
The injection mold stress line that's purple is exactly where my two twsbi cracked at
Thanks for the info. I havent seen any cracked ones so helpful to know
@@Doodlebud Maybe solicit a cracked one to look at for the follow up video.
I have a TWSBI Eco from bleskit, and after using it a lot I've come to realize that people are just screwing the cap on too tight. There's no thread lock so you can just keep going until it cracks
Its most likely an accumulation of multiple factors vs just one. The lack of a hard stop to prevent over tightening is just one more thing that can cause issues
Man u r a very curious person.
Thanks for the effort.
It was delight to watch the video.
Being curious is in my nature which is why I think I gravitated towards engineering. I just have to know how stuff works
One of my ecos has a little crack down where the feed goes in, sometimes (if the feed isnt blocking it) ink comes out of it and colours my fingers
Yes. Mine too. Within one year I had a ~3mm crack, and then a couple days later ~1.5cm crack. Also noticed a small crack in the cap. TWSBI covered it. I recently received my second replacement because of the same issue. Meh, I have move beyond TWSBI now.
Very interesting video. That polariscope will be and addition to my "home made" lab equipment and certainly I am going to look for that book.
It's a phenomenal book! That was my Christmas gift my wife "got me".
Wife: What can I get you?
Me: There's this engineering book I want to nerd out on
Wife: Done! Order it!
Me: 😁😁😁
Super cool I got Dan Gelbart to sign it when he had me over at his house.
I have 12 TWSBI pens and 12 Lanbitou 3059s. It has been over 5 yrs and I have had no cracking
with the TWSBI pens. The Lanbitou 3059, the knockoff of the TWSBI, has had no cracking issues
with them either. It appears from your demo that it takes a lot of torque/mistreatment to cause
cracking issues.
Definitive. Outstanding, sir!
Now the 823! That's another that's had reports over the years.
Very interesting. I'd like to see a follow up video with a TWSBI that naturally cracked!
Hey DB. If you put a polarizer filter on you camera, this will work much better. Just turn the filter on the camera lenses until the background (laptop screen) goes black. And any transparent object you view in between will be ultra high def to show the stress within the plastic.
I was going to order some proper filter material to do just that, but opted for the method where everyone can do this at home. I always enjoy finding the most basic & simple way to do something. Makes the challenge even more fun. But I'll probably order some proper filter material at some point. Also did it this way so when I get requests in comments for me to check this or that I can say "pull out your sunglass and give it try for yourself, only take 2 minutes 😁"
Unfortunately both of mine are cracked. Right at the end of the barrel right where the pressure spots are. I wonder if I was twisting the lid on too hard and not realising it.
😂 Its a fountain pen, if it breaks its not your fault. TWISBi is cheap chinesium
What's the glass transition (or is it just melting?) temperature of this material? (polycarb?) I have a heat gun that can go up to about 350c, so I would be curious if it would be possible to anneal the problem area to at least reduce the stress.
I don't think the eco is made from polycarbonate. Polycarb is very good for impact resistance so don't think the cracking issue would creep up. I believe it is made from some type of Acrylic (PMMA)
@@Doodlebud That is odd, Jetpens says that the body is made out of "plastic," which is often differentiated from acrylic. I do find it annoying that they don't say the materials on the official site however. Thank you for the starting point however.
Regardless, I ordered one and, I'll be getting it in on like the 3'rd, so I'll look it over and see what I can do.
Fakeedit: I looked it up and acrylics are technically plastics. Never thought of that, but it makes sense. Regardless, PMMA has a melting temp of 160c, so I may attempt something, hopefully without destroying the pen. (worse comes to worst, I just don't bother, wait and see if it cracks, and if it does just do remelt with some clay. Not like I can make it worse.)
Thank you again for the info.
Yeah the term "plastic" drives me nuts. It like saying something is made of "metal" and not differentiating what type of metal. When someone says "oh it's just made of plastic..." it let's me know they have no idea what it's made of 🤣
Everyone else: Why does the Eco crack?
Doodlebud: Let me science the shit outta this one! 😎
If there's an opportunity to science, I SCIENCE! 🤓
My 580 alr cap and clip just broke last week. It was in a pen tray. It wasn't even taken out. It had cracked when it was inside the tray. How is that even possible? The pen had been there for atleast a month.
It could have been contaminated. There are some chemicals that react with acrylic. Even something as simple as certain hand creams etc can have stuff inside that can cause damage. And all those need are time to let the reaction take place. For example I've seen parts fail in the field because loctite was applied to screws that come in contact with certain plastics and caused complete failures in parts.
Yeah Science! Another excellent video... Thank you Doodlebud once again!
Just spitballing here, but when I used to do a lot of laser cutting of certain plastics (specifically cast acrylics), the high stress areas, when contacted with isopropyl alcohol would turn into some serious cracks. Could those who experienced these cracks be trying to clean their pen with an alcohol pad or something?
Alcohol will for sure cause cracking, but I know people who've had their crack and they do not use any alcohol when cleaning their pens. In some cases there are reports of pens cracking just a few days after receiving a new pen and it hasn't been filled with anything other than ink.
Fantastic educational content! So glad this showed up in my feed
Glad you enjoyed it!
At least we know that the Chinese test pen (I guess it's a Lanbitou) won't crack under this severe (torque) test.
I really doubt that the ECO could stand this test - I would bet some serious money that it would have cracked way earlier! (Idea: ask 60 followers to send you 50 cents so you can do the TWSBI Crack Test 😂).
Had you done this video two weeks earlier I could send you the shot of my 580 cracked cap (right above the cap band).
Really enjoyed this video !
Thanks 😊
This was super fun for me to do! Just like the vacuum chamber test for flying with pens!
Parkers has the most durable body......Hope you do reveal why the Mont Blanc n Pelican cracks on its own ...in the shelves at room temperature for a pen which is valued more then gold . The world would appreciate your reviews. Tq so much.
✍️✍️✍️💚💚💚💚💚🌍🌍🌍
There are a couple reviews on jetpens talking about making sure you're not over tightening the cap as well.
It is fragile so handle it with care..
I've been using ECOs as my only pens for over 5 years. None of my ECOs have ever cracked.
No issues here but for some it happens regularly. This test at least gives something to consider
I’ve had my eco for about a year. Last week i noticed hairline cracks in the grip section close to the nib.
I’ve never disassembled it, dropped it or overtightened the cap..
I’ve enjoyed using this pen a lot for drawing, but I doubt I will purchase another because of this issue.
Cool!! Appreciate the sacrifice!
This takes me back to optical mineralogy.
Playing with optics systems is always cool 😎
@@Doodlebud Absolutely. Using it to identify the species of feldspar in a thin section of rock - less so. 😅
@@pnwesty7174lol fr
Hi DB, at about 2:00, your book, chapter 2.3.9., suggests to anneal the component for releasing the stresses. I have no idea at what temperature that would be for this plastic. Chances might be high that deformation might happen very close to the required annealing temperature and the cooling should probably happen infinitely slow. But isn’t it worth a shot? You could anneal the cheap pen you didn’t manage to break... 😅. Looking forward to your results.
Yup, annealing is something that is done. Just not sure if this was done or not but.... Only one way to find out
Pardon my francais; you're videos are f'inkg awesome! Finally, now I know it's not my fault. I recently got my replacement barrel for my replacement barrel for my Eco. I'd heard about cracking issues, but TWSBI made a point that they fixed everything for the Eco. And both times the Eco cracked at where you those stress points are. You did it with just those pieces of equip., and TWSBI couldn't do that. Shame. From now on, I don't think I am pulling the feed on friction fit, unless the casing looks study. Thanks for the info and video.
This was a ton of fun for me to do, testing and doing science is my happy place!
@@Doodlebud Part of me was hoping you were going to try and crack the Eco to see if it would break.
@@Doodlebud What if I ran the nib and feed and the section part under cold water? Would that help in anyway to prevent expansion of the parts and therefore stress and cracking?
This isnt a thermal expansion issue. The amount those grow with such a small part is extremely small. Like in the neighborhood of about 1 micron
@@Doodlebud What about a fluid dynamic issue. Perhaps it just needs some hydraulic fluid to help strengthen the plastic. Okay, I don't know what I am talking about. I just wanted to sound as smart as you.
Wow. I was gonna buy an Eco but after reading about all these cracking problems, I think I'll just stick with my Lamy Safari for drawing. I have a Pelikan M205 I use for drawing but I found out Pelikan doesn't sell any aftermarket nibs so it's not something I can but through a retailer...which sucks. At least I can buy a Lamy nib for $16 and I am drawing again.
Great video. Fun to watch D
This was even more fun for me to make!
Very interesting and informative, as always! My Vac Mini is a brick. I've had it for a few years. It's an EDC. No problems, so far.
The vac filler might be better, since they have to be made to more precise spec for the vac filling to work well, so perhaps that means the rest of the body is also more precise dimensioned. Also with the soft plastic between the pen body and feed it would avoid putting extra stresses on the end section during cleaning as that insert soaks up some of the rough handling.
I've had a vac mini for a few years and it was fine. Then, all of a sudden, hair line cracks around everything with a hard edge. Where the back screws in, edges of the cap, the section attachment point, etc. And I know it wasn't a hand sanitizer situation as it was only getting used at home at that point. REALLY weird.
@@Jarrych83 Ah, the mystery of the TWISBY crack strikes again. I hear so many of these at this point that I wouldn't buy any of their hard clear resin pens. The GO is safe as it uses softer plastic where it counts, although it does look like the cheap pen it is. Swipe might be also OK on this count, but that useless clip is just a nope for me.
@@martinlebl631 It's very frustrating. I do need to message TWSBI and see if they'll do anything. Lovely pen and a phenomenal size and shape for daily carry. But it's tough at that price when you're worried about the durability.
Cool!!! Nice video 👍
I have plenty of 580s and Ecos and they’ve all been superb. No issues whatsoever. That’s my experience anyway.
Mine too
I think if you don't handle the feed, and don't get a bad batch it is likely fine. I think the injection molding may go out of spec over time, and if no one notices soon enough you might have few thousand less than perfect pens go out that are prone to cracking. If no one notices, and it is brought back into spec by some routine maintenance, then it might be pretty hard to trace it. Which would explain why they haven't kicked it yet. The fact that they have a ready supply of replacement parts as an established program speaks volumes about the size of this problem.
I read sometime back that TWSBI made some changes to the ECO to address the cracking problem. I don’t know what those changes were, but I suspect they were formulation changes to the plastic. Maybe thickness changes around the nib end. Regardless, the TWSBI plastic is quite brittle. If you had jammed that screwdriver into one of your ECO’s I bet it would have cracked with very little moment stress. That’s my theory anyway, based on personal experience. Nice vid, as always!
twisbi had problems before eco, in 580 in mini in all their versions. Because its made out of chinesium
Definitely want to see that in the follow up video.
So you have to break it. I was going to buy the ALR because of the craking problem but I think I'm going for the 580 clear now 😁
Could weather, humidity, where you live etc influence the material of the pen and make it crack easier? 🤔
Would like to see this done on a 580. I had my 580 break and I never pulled the nib.
You could always grab your sunglasses and give it a try...... just saying 😬
my first eco broke right at the front where the nib touches the plastic of the body
I've had 3 ecos and a 580AL crack. Most of my pens have been fine, but the older ones in particular seem prone to the issue. It really does seem to be a luck of the draw sort of thing.
There's a selection bias in crack complaints. people know TWSBIs crack so if they spot one, they're more likely to gripe about it.
3 twsbi pens.. 4 cracks.. broken bodies.. caps. sections.. that material is brittle and develops lots of hairline cracks which build up. the cheap pen looks like it uses a softer plastic, which may be why it holds up well.
Would a lighter’s flame reset the stress point in the plastic? Or would that make it worse? I have a TWSBI Go which happens to be my oldest pen and it’s also my work pen, so it takes a beating. No cracks. I’ve gone through two TWSBI Ecos. One cracked falling from pocket height onto carpet. And the other fell from shoulder height onto tile. If I ever buy another TWSBI, I’ll stick with the Go. It’s hella cheaper and I like one handed refilling. I don’t want to buy any of their more expensive pens because of cracking. Wish TWSBI didn’t make solely demonstrator pens.
If you give the lighter method a try all I ask is you please video record your findings! LOL😆
@@Doodlebud will do. Guess I'm buying one last Eco lol
Well TWSBI does make non demonstrator pens. Precision, Classic and Draco, are either metal or opaque plastic pens.
I think Go is made from different and softer material than ECO and Diamond models.
I've never used a twsbi go but I don't think that it's acrylic, more than likely a more resistant type of plastic, possible that's its polypropylene.
@@korax67 Yep, feels like you could gauge it with your fingernails, but I don't think it will crack. And it is cheap enough that if you use the nib elsewhere after it fails it is still worth it.
They just sell millions of the TWSBI Eco, so even with a failure rate of 0.1 % every one million pens sold 1000 people end up with a broken pen. And I don't know the sales numbers but I know that this pen is very popular and most people don't only own one of them ^^
oops, I just continued the video and you thought of the same reason for the "high" number of complaints ^^ sry
Are you AVE? Do you know his channel? You sound just like him. Either way I enjoy both channels very much! THANK YOU!
LOL I know of his channel. Lots of people ask if I'm the same guy, but I always take the comment as a compliment 😁 Glad you're enjoying my vids
Id love to see the TWSBI go through that torture test. It probably would break well before the knockoff would.
Very cool stuff!! It would be nice to have a way to "see" the stress in non-demonstrators too.
For me, the Eco piston function didn't work and would unwind itself after filling. No cracks as of yet, just useless in another manner.
We don't know for sure if thats the issue. There are endless variables in tracking down the real source of this problem. This type of thing could easily take months for someone to track down specifically working on this type issue (I've done stuff like this in the past). Some people have reported the pen cracking almost immediately. I'm more leaning towards an issue during the injection molding process (most likely heat profile) or post processing. The heating/cooling profile is the major cause of internal stresses for these types of parts. It can also be in tiny features in the design of the pen. The stress map shows its concentrated at the end of the section and only comes down about 2-3mm into the section. It could be the change in contours at that region without the correct material thickness or supports can cause hot spots in the stress map. Large profile changes over small distances are common stress points.
@@Doodlebud Doing injection molding well is harder than people realize. And any corners you cut, or the press, or cooling lines going out of spec is going to have consequences that might not be immediately apparent. My theory is: (1) something goes out if spec, (2) molding makes problematic pen bodies which go out into the wild, (3) no one notices this problem, (4) it is brought back into spec by routine maintenance performed as schedule. Now when the cracking is reported in the wild, it is very hard to trace the cause.
In non transparent materials you could use infrared/thermal imaging, or x-ray imaging to observe the stresses, but that isn't quite so easy to improvise from items you have on hand, unless you have some mad scientist lab in the basement.
could they be more prone to cracks due to climate even moreso than reoccuring stress? From what ive noticed, people who had one cracked eco/vac/580 seemed to live in colder climates
What pen is the “ Twisbi- like” pen?
Can remember. Some $2 special from Aliexpress
Mine was fine until I dropped it three feet onto a concrete floor. I emailed TWSBI and they're sending me a new section/barrel.
Once I get it I'll keep the same nib in there and likely not travel with it... Too fragile.
I would have thought that the contours show the variation in stress. So, you could have a pen that is uniformly highly stressed and shows no variation... Which could be as likely to crack as one showing variation (lots of contours)?
Also, I should think that different materials will refract light differently under different ranges of stress, so comparing different pens (plastics) would be difficult.
Finally, there's the difference between hard (brittle) and (soft) tough materials. So, whilst we may not want our pens to crack, we also would like the "quality" feel of harder plastics.
I can see a lot more experimentation here, crushing various pens and measuring the load and displacement!!
The first question about stresses is far to long for me to give input in the comments. But if you want to learn more read up on "photoelasticity stress analysis" and that will fill you in
Part of the reason that the only TWISBY I own is a GO, as that is a pretty soft plastic that wouldn't be prone to cracking, and would likely stretch first. Of course it doesn't look pretty, and is very much on the functiona side of things.
I had 2 twsbi pens, 580 and vac mini, both had cracked in different places, for both , I got replacement part from twsbi, later both pens again cracked in different places, I just gave up, savaged the nibs and throw the pens in frustration, never going to buy twsbi again.
Unique!!! 😎
I bought a beautiful and nice 580 with a stub 1,1mm nib but destroyed it just one month after buying it because of ink in poor condition..smelled like ammonia but I noticed it too late..
I have a lot of Twsbi's -- The only problem I had is when I acidently spilled alchol on a cap, and it basically ate it. Twsbi sent me another cap. Also, I lost the o ring from the orginal Vac 700 and they sent me a new one.
Their customer service seems really really good!
@@Doodlebud Their Customer Service is wonderful. To anyone who has a crack in their Twsbi's I would strongly recommend to contact Customer Service to get a replacement part. Their Customer Service is the reason why I will keep buying Twsbi's. But I haven't experience a crack in any one of my over 30 Twsbi's I have. Not to say it doesn't happen, I just haven't experienced it.
I thought they fixed the cracking issue.
So did they.
@@martinlebl631 : (
Lol, this video was cute, but the reason why the Eco's are cracking isn't because of "stresses" placed on it as force.
It's the material that it's made out of, any alcohol or ethanol interacts with the acrylic it's made with.
I discovered this after some research when my pens were cracking.
I would clean them with an alcohol mixture, and cracks would start to form the next day.
Some inks have low amounts of alcohol in them or ethanols for various reasons and their recipes are mostly secret anyway, but the low levels of any of these chemicals will slowly start to crack the acrylic. I was cleaning my pens with 70% rubbing alcohol and they would crack the next day. Brand new pens too.
I'm very aware alcohol makes acrylics crack. But claiming that the only reason a pen cracks is from exposure to alcohol is a giant assumption. People have reported cracks from using it only a couple of times. And this is well before Covid with everyone using hand sanitizer. I'm not claiming that the stress points are the reason either. But the reported cracks align where these internal stresses concentratios are seen. Photoelasticity is a very common way to inspect parts for these exact types of issues. The truth is none of use know the exact cause of the issue. Also it is advised to never use alcohol when cleaning pens, so that's not a good idea to begin with.
@@Doodlebud I actually spoke to the rep at TWSBI when I was reordering them and describing my issue. They were the ones who told me that ethanol will crack it. He says majority of cases are from manufacturers that use some form of ethanol in their inks or someone cleaning their pen with it.
@@Doodlebud What can cause acrylic to crack?
When acrylics come into direct or indirect contact with harsh solvents, the liquid or fumes may cause a drying effect that stresses the material to the point where it becomes brittle and suddenly cracks and/or crazes. This is due to a chemical reaction occurring between the solvent and the acrylic.
@@Doodlebud Something as innocuous as cologne can cause this. There are a myriad of things in households and around us that would cause these cracks. Sometimes it may just hairline crack it and the act of writing would put enough pressure to stress the crack further.
From the point of view of continuum mechanics, plastics are fascinating.
I'd love to know your background. "Continuum mechanics" isn't something armatures even know exists
@@Doodlebud retire professor of applied mathematics (Georgia Tech) Graduate degree is from Carnegie-Mellon, where I had several courses on continuum mechanics.
That would explain it LOL
@@Doodlebud You sound like you work in a lab or some sort.
No any more, I'm now a financial planner. But used to work in precision laser measurement equipment. All the way from R&D, design, manufacturing, assembly, test, install, & support. I bring up some things from that world to talking about fountain pens oddly enough 😆
I love them but they have some issues. Specially the feeds start very wet and then go dry so fast
As much as I thought my money would be going to a new pen sometime in the future, now I'm super excited to get that book Building Scientific Apparatus XD Lol. Hmmm, I'll first see if my library has a copy I can borrow cause. I'm sure that's gotta cost some big bucks. 😅
Enjoying your unique approach to fountain pens. Any chemists willing to review inks
I'll just get an Asvine P20 or V200 instead. Both better prices, and significantly better pens.
Quick note on "using your phone screen" - AMOLED phones won't work, they have to be LCD. A lot of modern phones are AMOLED these days, and they do not produce polarized light.
Ahhh yes forgot to mention that, thx for bringing it up 👍. Fun to find the most simple way to DIY something to do the quick & dirty test
Perhaps your 'sacrificial' pen is made from a different plastic or plastic mix to the TWSBI - one that is actually tougher?? In my experience TWSBI pens are a brittle sort of plastic. I doubt any would have survived the treatment you gave the poor sacrificial one! I was put off TWSBI years ago because of cracking issues I had. I am amazed that all these years later the issues clearly have not been resolved. Until they are I wouldn't buy a TWSBI.
Yeah it will be a different plastic. There is a trade off in getting such a clear pen body with the Twsbi but in turn the body becoming more brittle.
I have eight TWSBIs, four of them Ecos, and none has ever cracked.
Yeah...its that kind of plastic that has the potential to crack that I don't like with the ecos..they are great pens...but if it cracks..goodbye dry out protection.
Very informational video again! I will try to do the same at home to see the stress pattern around the cracks in my two cracked TWSBI ECOs. A scientific minded TH-camr like you is exactly what the fountain pen community needs to help objectify things. On a separate note, I can't believe that a big guy like you couldn't break that cheap little pen! Lol, JK :)
Best comment so far! "I will try to do the same at home...." Lots of folks giving conclusions, but few saying "I have an idea of what it could be, let me do some tests and see."
That pen is a tough little F**ker! LOL I could have gone harder but I was started worrying about the amount of energy I was putting into the pen and was very aware its going to release at some point and go BOOM!
@@Doodlebud Exactly! Almost all pen reviewers just give their opinion on pens which will almost always be biased. Your videos, because of their scientific basis benefit everyone equally🙏
I wasn't really talking about reviewers, it was more folks on forums, comments, etc. It amazes me how the work between hypothesis and conclusion seems to vanish. "Here's what I think is going on..... therefore that's what's going on"
@@Doodlebud Yes, true!
@@Doodlebud It might be that the cheaper knockoff is made out of cheaper softer plastic, which doesn't look as shiny, and scratches more easily, but is also more pliable, so it bends instead if cracking, while the harder shinnier plastic of the ECO cracks as it cannot give. Perhaps comparative screwdriver test, a la Project Farm could settle that.
I doubt pen retailers would continue to promote them if they were that bad.
At least you buy a silicone grease at the price of a pen, they are such a nice company because they know how to sell cheap plastic, that's for sure.
Interesting analysis, just don't stress your pen in front of your laptop screen with a screw driver. You run the risk of slipping, and smashing the pen + screwdriver through the screen.
That's why I called it quits. There was so much energy going into the pen it was going to get released at some point in a very rapid way. Either big BOOM or hand slips and no my laptop is a custom screwdriver holder
So what this tells me is that the knock off is better built than the twisbis. I bet you the screwdriver would have cracked the twisbi easily.
They are made from different plastics so they have different properties. The build quality on the knock off is terrible, but the plastic is more flexible
My twsbi was delivered in sub zero temperature and when I opened it the thing was riddled with micro cracking. Substantial. Terrible cheap pens.
Sorry, but the nominative plural of “apparatus” is not “apparati,” but “apparatūs,” with a long “u” in the last syllable. Although “apparatus” may look like a second-declension noun, it is in fact fourth declension, like “genus” and “spiritus.” For those of us who wasted our time getting a Classical education, Latin is not yet dead enough that its grammar ought to be completely ignored.
Sometimes I also mess around with how I say things just for fun ;)
IMO get a GO if you really want a TWISBI and not care about looks
I love it when science meets overhyped writing tools.
In a fit of frustration, I threw out my three TWSBI Vac-700s. I saved the nibs. I bought all three pens about 6 years ago, in 2016. In all three cases, the section literally cracked and broke near the bottom. So it's impossible to fix. An analogy would be a broken light but with the base still screwed in. TWSBI should be ashamed of its quality control. There is none. Google and ye shall fined hundreds--literally hundreds--of complaints regarding cracked TWSBIs. In my case, the nature of the failure rendered the pen impossible or uneconomical to fix. So, to part ways with the company, I tossed their products where they belong: in the dustbin of my history.
TWISBI is less strong than a knockoff. Ridiculous.
You sound strinkingly like another CNC/ tool youtuber from canada, “AvE”
LOL, yeah I get that comment fairly frequently. I grew up in the area he lives so perhaps we share some of the same lingo
The knock off is better than the wtisbi crap.
✍️✍️✍️✍️✍️💚💚💚🌎🌎🌎🌎🌎
Better be wearing your safety squints…
I was safely protected by by phone and my cat like reflexes