As a welder in all forms of welding for over 50 years I think you make some valid points and useful tips for beginners. One point that I would like to elaborate on is that brazing does not have to be a slow operation, many years back bicycle frames had sleeve joints just as you mentioned and showed a picture of. The whole bicycle could be assembled and heated until the braze and flux melted this process could be done as a one off or hundreds of units were sent through an oven. This process is used extensively today in industry. With thin wall tubing the process is reasonably efficient and reduces the effects of localized stress that can be a problem with other forms of joint manufacture, especially if you are using high strength alloys. Low temperature brazing alloys may not require the assembly to undergo further heat treatment. Tig welded mig, gas, or stick joints produce high stress riser points so compensation has to be made to ensure failure does not occur at these joints, this usually means increasing material thickness.
Fillet brazing is a dying art for sure. When I got hired for a high end tandem bicycle manufacturer it was my ability to fillet braze that got me the job, they had been trying to hire someone for 2 years with no luck. Learn both, it comes in handy especially bicycle frame building.
I would add that one potential dissadvantage of TIG welding is the subtraction zone which happens next to the weld bead. If the tubes you're using are already very thin this subtraction zone caused by hot semi liquid steel being drawn towards the weld bead can cause a weak area to form right next to your weld.
Don't stop teaching dude. Youre great at it! Better then my university teacher at least. I got a crack and got nothing to fix it. Im studying a way to just get it from falling apart. If any on would like to look at it would be greatly appreciated.
I suggest you to drill a clean hole in every end of the crack, fill it and weld the crack, brazing doesn't work in this case, in case you're thinking about the holes it is to reduce the stress concentration in the area.
On a side note for 303 stainless: All free-machining alloys have lead added to them, and lead melts at 620F, while the TIG arc is 10,000F. The lead boils out and causes issues with your shielding gas. So, you do get a weld, but it's not as clean or free of porosity as a comparable non-free machining alloy would be. -- Similar issues happen with brass, galvanized steel, and zinc plated hardware. The zinc in those alloys goes through a similar boiling event, plus you breathe it in, and that's no-good. -- TIG brazing is able to deliver results very similar to oxy-acetylene if you purge the tubing with argon. The scale and oxide is what stops the bronze filler from sticking to the joint materials. If you're careful, you can actually TIG braze stainless without an interior argon purge. -- Hexavalent chromium is present when you heat stainless enough to turn it grey without argon shielding, so bright yellow hot. When you grind stainless without coolant, or create stainless weld sparks via MIG or SMAW, that's when CR(VI) becomes something you should be aware of. Hexavalent chromium is listed as a "probable" cause for lung cancer. So, don't lose sleep over it. If you cut stainless with a chop saw or angle grinder, do it outdoors. If you sand stainless, you should be just fine, but you will become a better craftsman if you use soapy water as a coolant and lubricant during the sanding process, which applies to ALL metal sanding.
I am very happy, that a guy your age has masterly knowlegde and is able to explain that knowlegde in such a good way. I am happy that craftsmanship is still outa here
I really enjoy your videos. There are couple other advantages that TIG has over brazing that you didn't mention. The first one is that TIG arguably produces a stronger frame because the heat affected zone of the joint is much less. The TIG torch produces rifle like accuracy whereas the brazing torch has more of a shotgun like effect spreading heat into a much larger area. Secondly, all things being equal, the frame that is TIG welded will be lighter than the frame that is brazed as the TIG joints will have less filler material in the completed joint. Keep up the good work Joe.
Yes, but also no. I think that TIG (fillet) brazing takes the cake here. The problem with actually welding highly alloyed tubes like these is that when you make a puddle with the base metal you are actually pulling the alloying elements to one place and you are creating a brittle zone there. That is why any weld will always fail and crack right next to the weld. From a metallurgical standpoint welding alloys is a shitstorm. TIG brazing will keep the basemetal the coolest and strongest at the expense of a few extra grams of bronze per frame. We are talking about maybe 30-40g of bronze per frame after the fillets have been filed compared to 10-20g of steel filler wire if TIG welding.
At 3;00 you showed hard copper pipe. I have successfully welded the fittings of this type of metal, using copper rod and Oxi/Acet. John Chaplain's comment is valid. Torch welding steel is a beautiful thing. Over TIG, you have more control because of the lower temp. and the puddle is really thick (not runny) so there's plenty of time to pull the puddle around and get superb penetration.
Exactly my words as I was thinking it you was saying it. Soldering / Brazing even with the plumbers example exactly my thoughts. I'd never fillet braze not enough surface area for my liking.
I don't think that the amount of material in the brazed joint adds much to the strength. In fact, I think you'll find that the less braze there is in the joint (ie the closer the sliding fit), the stronger it is. The fillet is there to spread the stresses. As I recall, the molten braze diffuses into the parent metal and forms a microscopically thin intermetallic crystalline alloy at the surface. The joint isn't "glued" (like a joint in wood, for example) but the metals are joined on the atomic level.
I'm starting to get into brazing and so far I found I really love using a propane torch and silver filler. I don't need to mess around with acetylene and the silver makes such beautiful clean small fillets with barely any post processing. I really wanna see if I can build full frames with this. If I can get the prep work to fit the tubes nicely quick enough I think the price of the filler can be offset by how quickly it brazes into a nice little fillet
I am old. I braze everything. I don’t do aluminum, but they do make aluminum brazing rods for the HVAC industry and others, however it’s very difficult and I have no idea if it would work for bicycles. I have tried it on scrap lawn furniture as an experiment. If it can be done reliably and consistently it’s very difficult. You would need a very good system figured out and lots of practice. Not worth it. The aluminum is hard to read. It will melt long before it would glow red. You really have to braze with an air tip at the most. It just turns to butter under a torch. It’s very hard to repair a melt through. Great info and video.
When I was cycling seriously back in the late 70s and early 80s, the concern was always overheating and damaging the tubes. This was in the days of Reynolds 531, 753 from England, Columbus from Italy, Vitus from France and Ishiwata and maybe Tange from Japan. I seem to recall you needed a license or certification to make 753 frames because they were very delicate. I would guess that once TIG welding came along, tube development has occurred to allow for use of the process without compromising the characteristics of the tubes. Back then, braze-ons were frowned upon in the UK ( Italian bikes had them everywhere ) and chroming was discouraged, again because of potential damage to frame integrity. My impression is that you can silver braze anything as long as you don't overheat but I wonder about TIG welding. Just checked the Reynolds site and they pretty much seem to be saying that they made their newer products TIG friendly.
1) What state is your shop in? 2) How much would you estimate it would cost a noob to procure a quality Brazing and TIG rig? 3) Kindly list your estimate$ of each and brand preferences. 4) Do you use BikeCad or another 3D CAD modeling software? Thank you for such articulate, inspiring, and imformative videos. Have a wonderful Holiday season,phil
Very impressed with your knowledge for being so young. What many are missing though, is inline liquid flux. If you are welding frames more than once you should be using it. I used to braze bike's and wheel chairs in a production environment, and you can fly when brazing, with minimal clean up. I also Tig welded for all kinds of frames. Both like you state have pros and cons. Man, I can't imagine how much you will know in ten years from now. Try the inline flux, you will laugh that people still use paste. You can braze faster, cleaner and have more control over where the brass goes. Of course the tip size is also a factor along with how quickly you can move. Skill level is the most important factor, but it come down to practice like anything else.
Really enjoying your videos, man. Do you do any rack fabrication? I've done frame brazing but it's been hard to find any info about fabricating racks. Tubing used, how to best bend tubing, etc.
Does tig welding make for a stronger joint than brazing? You would think so if it actually melts the 2 components together, whereas brazing only melts the filler material to act as a glue. That's my interpretation of the two situations. Correct me if I'm wrong🤔
Hi I have a question. Can I fill a small crease in thin bicycle tube with silver solder and a simple propane torch that does not use acetylene? The tube is seat stay about 10 cm from the drop-outs.
Good stuff. In brazing you’re actually seeping in filler underneath the two materials to join them and get that semi-fillet curve going as you call it. It’s also way easy to go the other direction and glob too much filler and concave the braze round. That case lends the possibly to joint failure as you don’t know if the filler actually seeped and sealed the joint. Advantage to TIG, I think is even if you’re burning holes in joining materials you can cover them and ensure you’re getting a good bond. My two cents from trial and error and a certain school of thought. Thanks for posting.
I was surprised you didn't mention one advantage of welding (including bronze welding) frames, which is that you're not restricted to the sizes and angles of available lugs. High-end TIG welded frames took off around the same time as mountain bikes, I suspect for this reason.
Hey there I have a question. I have an aluminium folding bike, and I want to add a better fitting basket on the front. It doesn't have mounts. I have considered drilling into the frame and adding a klickfix, or brazing a custom mount onto the front that I can slide a custom made basket into. What do you think? Better to to sand down a bit of the coating and braze, or better to drill and set a couple holes? Thanks. :)
The hexavalent chromium is no an issue when TIG welding stainless, only when MIG welding is it a problem. TIG welding stainless does expose you to ozone (small particles). Proper ventilation is the key here.
I have tried that once or twice, but once I really had my own TIG machine in my shop I stopped building bikes with fillet joints, so I never got that far into it. I have heard it works well, but I don't know who does it. I would talk to some of the fillet builders who also have TIG machines around -- they have all likely tried it.
It would be fine for a low-end steel frame but not for lightweight alloy steel tubing. For adding a disk mount you could probably use silver solder and a propane torch but you'd need to take a lot of care with the fit and cleanliness.
RE: Old school brazing into the 80's and 90's- the advent to of steel alloys that air harden made the move the to the higher temperature process of welding workable for high-end bikes. Previously, tubing was heat treated from the factory, and the thinking was that brazing allowed better heat control and less risk of killing the temper on the tubes. Reynolds 853 really did change things a lot- it was, to the best of my knowledge, the first premium bike tubing that was designed for welding (or, in some cases, high temperature brass brazing).
When Reynolds first came out with cold worked air hardening 631 and heat treated air hardening 853, Reynolds approved welding the thicker, softer 631 and only brazing the thinner, harder 853 tubing. Reynolds originally recommended against welding 853. When Reynolds later decided to approve welding of 853, I did start seeing welded 853 frames that had cracked. Is this due to being heat treated or is it due to the tubes being so thin? Most other tubing companies that sell air hardening tubing, sell in it only in the heat treated, hardened condition, so I think the welded 853 frames are cracking because the tubing is so thin and difficult to weld properly, because it is so thin. It is interesting that Reynolds originally recommended only brazing 853, while the thicker 631 was approved to be welded. Maybe they knew something all along. Other than the thicknesses of the tubing, the thicker 631 is not heat treated and the thinner 853 is heat treated. Is it thinner than other tubing companies' heat treated air hardening tubing? Reynolds has a chart with the hardnesses before and after brazing. High temperature brazing is recommended of the air hardening tubing. The 631 would become harder at the brazed joints and the 853 would become softer at the brazed joints, but the brazed 853 hardness was still higher than the brazed 631 hardness. I've seen too many welded 853 frames crack to recommend welding 853, but I do like air hardening tubing for bicycle frames. Maybe the other brands ren't hardened to as high a degree of hardness, or maybe their tubing is thicker and less prone to cracking when welded. The thicker, softer 631 doesn't seem to have the cracking problem when welded and other brands, which most all are heat treated, seem to weld alright. I think 853 survives best when brazed, but might be on the thin side for crack-free welding.
I came here to get some light on to why some mtb steel frames made in Taiwan are much more (we are talking 300-400USD) expensive (I think of Surly Krampus or Ritchey Ultra) than others also made in Taiwan (like Sobre Off or Nordest Britango). Are the expensive ones TIG welded and the cheaper ones done through a cheaper, less quality method? ALSO, some frames have only 1 gusset on the downtube other only on the toptubes, and apparently they are all regular 4130 double butted tubes. Does only 1 gusset make it cheaper and therefore more prone to braking the frame in the long run? I got excited and I asked too many and complicated things. I will understand if you ignore my message
I need to ask you a question, I used to ride a re unbent trike, and a car hit me fractured the frame and eventually broke a part, so I’ve been looking for somebody to do so, but because of COVID it is hard to get somebody to do it, where are you at so perhaps you can’t take a look at it. I thank you before hand and hope to hear from you Carlos
In the 1970s I was a flame Brazier for Huffy bicycles so let me tell you how it was done son as soon as you picked up the torch off the economizer valve the gas came on allpria justed the flux was mixed in with the settling we use the number 5 tip with the valve for the settling crank all the way open the regulator's cranked up to the max then you would turn the oxygen up to you had a oxidizing Flame two welders could put out 60 frames an hour not counting for spot weld and the head to was done separately the wells got a visual inspection dipped in a cleaner and painted no cleanup at all it was all about speed speed speed baby because Huffy bike were cheap cheap cheap
Oxy acetylene welding from my experience is the lowest cost way to weld or braze. Go price everything necessary for OA welding and look at the cost of a tig machine big cost difference.
Very useful information, thank you. My frame recently cracked where the seat tube joins the bottom bracket. It is a steel frame from the early 1980s (Centurion Super LeMans), which I understand was made from "double butted" steel tubing. I was planning to take it to a welding shop for repair. Do you think TIG or brazing would be better? Thanks again.
Good question. I know on motorcycle frames they always crack where the seat post joins at the bottom. Have you thought about stripping the paint or coating off the areas you are concerned about and having a shop Magnaflux that area and mark out see exactly where the crack starts and stops ? That is what I do when someone brings me a cracked frame I strip it down clean and magnuflux test that entire frame with my magnet and shaker of iron powder because I want to be able to go to bed knowing that frame will be safe.
I found an old Roadster Bicycle frame with a broken but brazed Bottom. How strong enough could I assume the Bottom to be, compared to its original make ? Appreciate an early reply ! Thank you !!
I was wondering if TIG brazing could work too? What do you think of TIG welding it first and filling it up with SiB & TIG brazing (just for the nice look of it). I am welding in my basement and Oxy-Ace setup is just too dangerous there due to poor ventilation, still I TIG braze random stuff a lot for the sake of the fillet-brazed look. Thx in advance!
Kmart and Walmart bikes are TIG welded, or simply spot welded. Very uneven heat (6000 degrees), and poor frame tube adhesion (joining the frame tubes together) are the result. These kinds of bikes are produced in the masses, not quality. I’ve owned a few of these bikes, they’re junk. Brazing, on the other hand 🤚, is done at a WAY LOWER temperature (and even heat, too) 🤒, resulting in a VERY STRONG bicycle frame. Such a bicycle frame could last up to, and past 10 years, and is VERY WELL worth the investment. Your friend, Jeff.
Thanks for the info. I’m building a motorized bike with the standard kit mainly, if you’re familiar with that. I need to mount a gas tank onto the top horizontal bar of the frame on a men’s bike, thinking about brazing, any thoughts on that? Thanks in advance! Edit: steel frame
Old motorcycle frames and the old springer front ends were furnace brazed together so you have brass inside of your tubes. Guys who modified old springer front ends making them longer using old ford radius rods brazed or welded them safely with oxy acetylene. The book I learned from for motorcycle frames is Custom Chopper Cookbook by Mike Geokan check it out he builds gorgeous frames for the street and for land speed racing. I am really glad I found your channel I really like your work and appreciate your sharing your knowledge.
Hetchins were once asked by an American interviewer how long it takes to file their brazed fillet joints to that beautiful finish. The very indignant answer was "We do not ever file our joints at all."
I need help. I have a fixie steel frame i think its chromoly and i already hammered the inner chainstay so i can fit ma wide tire. So here is my problem i want ti fit a 700c x 45 on it but it hits the inner chainstay. My solution is find someone that can cut and weld new rear triangle of the bike is that even possible and safe if it si
It's doable to replace the chainstays. It's probably not cost effective. Being happy with what you already have is going to be the cheapest. If you must absolutely have fatter tires getting a different frame usually makes more sense.
hmm 6011 in 3/32, 1/16, fish mouth with a little space for the material of the electrode, i try with 6011(3/32, 1/16, 1/8), 6013(3/32), 7018(3/32), 7014(3/32), i fk smash with jumps and hammer the frames and don´t have any problems with the stick welding, tube of steel 1,5 mm to 2mm that work for me, i try repair a tange tube with stick welding and fking destroy the frame is a bad idea stick weld a thin tubes
Well, I think generally you’d need pretty thick tubing for MIG to work well. Thick tubing makes really heavy bikes, which are fine I guess, but man I don’t want to ride a 40 pound bike. If I’m going to the trouble to make I by hand I want to make it NICE.
Hey thank you so much! Is there any way to make lugs without machining them on the mill or buying presized ones? My dimensions are a little abnormal and I'd like to reinforce my joints with a basic lug of maybe just slightly larger pipe
You can make your own for sure. You need tubing that has the right slip fit over the inner tubing size. In USA if you buy the outside tubing 1/8” larger in diameter with a .058” wall it will have a nice slip fit over. So if you have a 1 1/8” tube and want nice sleeve material the easy way is to get 1 1/4” tubing with a .058” wall. .058” wall is kinda chunky so you still might want to turn that diameter down on a lathe if you have the means.
I don't know too much about brazing aluminum, but my understanding is that it is not actually practical for frame construction outside of cable guides and small bits.
I was able to get my hands on some stainless tubing for cheap. It’s about 1.5” OD 035 wall. Not sure what type of stainless. Question is, can I braze a frame together with it? I brazed a 4130 frame years ago, so think I can do again, but don’t want to buy a torch if I can’t use on the stainless. Guy at weld shop says SS can’t be brazed, but wonder if that doesn’t apply to bikes where metal mass if very small and therefore maybe can get hot enough. Thoughts?
"wonder if that doesn’t apply to bikes where metal mass if very small and therefore maybe can get hot enough" Repeat this to guy at weld shop and see what he says.
Chris Mason people do braze stainless even though manufacturers don't generally recommend it. However, they seem to be O.K with brazing when using lugged construction. As you don't know the alloy I wouldn't try brazing it without lugs. Look at silver soldering it too, that'll keep the heat down.
Anonomosomous appreciate the comment. Lugged brazing is more for the classic bike design and method. The one frame that made was brass fillet brazed (not lugged). It was on 4130 and lasted over a decade with a lot of abuse. Wondering if there’s some reason this won’t work on SS. I think I’ll just have to make samples and test to destruction. Thanks again
I'm not sure why he said SS can't be brazed, because it can be. Now everyone here seems to be talking about brazing with a torch, and mostly sweating connections and maybe that is where the trouble is? I have and many others have TIG brazed SS with out issues. You can get away with out having to purge. Some stainless welds badly so without knowing what you got...
In the old school you had "transformer" welders that were the size of a fridge and they used a lot of current so they were always 220v single phase or even 440v or three phase. Since "inverter" welders have become common there are a lot of options that will operate on 110v. They don't always have as much output when you run them on 110v, but they generally have plenty for welding thin wall bike tubing. My Everlast welder is this style. Also, wiring a 220v outlet is generally a pretty approachable DIY project and there are a bunch of youtube videos about that topic.
Kind of "what he said". Inverter TIG welders can do about 140 amps on 120V and that is enough to weld up to about 1/4", so much thicker than anything you are likely to deal with on a bike. Also many of them are dual voltage and can run of either, you just get more amperage available on 220V.
@@skoue4165 I used to TIG weld constructions from 1" and 2 3/4" with 1/8" wall aluminium tubes. The welder was usually set to 190-220 amps. Anything lower would just take way too long although I started off at 140 amps until I got better at it.
@@cobraframebuilding if you getting 220VAC then there is something wrong with the wiring or the transformer outside supplying power too the electrical meter because the nominal standard in the USA is 120VAC and only allows for a range of −5% to +5% RMS. Note: The 240Vac is two legs so its 120+120.
Any frame can be modified just take your time and fitting it up, measure, check, and see if it works. I have no college education all I have is learning from my father at a very young age, my own projects, job sites, figuring out what works, and what doesn't work. The best framework starts with that one question will this modification work ? The person builds something that works or learns how to make it work even better than expected. Best wishes and good luck 👍
When I was a kid in the '80s I was reading a book about road bicycles at the library and the author turned his nose up at welded frames, claiming they were inferior to his beloved lugged & brazed frames, and only found on cheap department store bikes. I knew he was full of shit because all BMX frames, including top-of-the-line ones, were (and are) welded, and they have to be a lot stronger than a road bike frame, considering that they have to handle big jumps. Mountain bikes were just becoming a thing at the time, and their frames are typically welded too. They also have to be stronger than a road bike frame, for obvious reasons. If he's still alive I wonder what he thinks about it now that even high-end road bikes have welded frames with no lugs.
Once upon a time the highest quality best regarded tubing for bike frames was Reynolds 531. Reynolds 531 lost a lot of strength with the higher heat from welding vs brazing. Reynolds 531 used a manganese steel alloy with strength as well as most other properties comparable to 4130 cromo except it's ability to withstand higher temperatures associated with welding. The bike industry found that welded bikes were cheaper to make than brazed (fillet or lug). Thus welded steel took over. Welded steel was eventually found to make a stronger joint than brazed (although good examples of each are both excellent).
As a welder in all forms of welding for over 50 years I think you make some valid points and useful tips for beginners. One point that I would like to elaborate on is that brazing does not have to be a slow operation, many years back bicycle frames had sleeve joints just as you mentioned and showed a picture of. The whole bicycle could be assembled and heated until the braze and flux melted this process could be done as a one off or hundreds of units were sent through an oven. This process is used extensively today in industry. With thin wall tubing the process is reasonably efficient and reduces the effects of localized stress that can be a problem with other forms of joint manufacture, especially if you are using high strength alloys. Low temperature brazing alloys may not require the assembly to undergo further heat treatment. Tig welded mig, gas, or stick joints produce high stress riser points so compensation has to be made to ensure failure does not occur at these joints, this usually means increasing material thickness.
Fillet brazing is a dying art for sure. When I got hired for a high end tandem bicycle manufacturer it was my ability to fillet braze that got me the job, they had been trying to hire someone for 2 years with no luck. Learn both, it comes in handy especially bicycle frame building.
I would add that one potential dissadvantage of TIG welding is the subtraction zone which happens next to the weld bead. If the tubes you're using are already very thin this subtraction zone caused by hot semi liquid steel being drawn towards the weld bead can cause a weak area to form right next to your weld.
Don't stop teaching dude. Youre great at it! Better then my university teacher at least. I got a crack and got nothing to fix it. Im studying a way to just get it from falling apart. If any on would like to look at it would be greatly appreciated.
I suggest you to drill a clean hole in every end of the crack, fill it and weld the crack, brazing doesn't work in this case, in case you're thinking about the holes it is to reduce the stress concentration in the area.
On a side note for 303 stainless: All free-machining alloys have lead added to them, and lead melts at 620F, while the TIG arc is 10,000F. The lead boils out and causes issues with your shielding gas. So, you do get a weld, but it's not as clean or free of porosity as a comparable non-free machining alloy would be.
-- Similar issues happen with brass, galvanized steel, and zinc plated hardware. The zinc in those alloys goes through a similar boiling event, plus you breathe it in, and that's no-good.
-- TIG brazing is able to deliver results very similar to oxy-acetylene if you purge the tubing with argon. The scale and oxide is what stops the bronze filler from sticking to the joint materials. If you're careful, you can actually TIG braze stainless without an interior argon purge.
-- Hexavalent chromium is present when you heat stainless enough to turn it grey without argon shielding, so bright yellow hot. When you grind stainless without coolant, or create stainless weld sparks via MIG or SMAW, that's when CR(VI) becomes something you should be aware of. Hexavalent chromium is listed as a "probable" cause for lung cancer. So, don't lose sleep over it. If you cut stainless with a chop saw or angle grinder, do it outdoors. If you sand stainless, you should be just fine, but you will become a better craftsman if you use soapy water as a coolant and lubricant during the sanding process, which applies to ALL metal sanding.
Dude your channel kicks ass. You've got a video for damn near every question I've ever had about frame building.
I am very happy, that a guy your age has masterly knowlegde and is able to explain that knowlegde in such a good way. I am happy that craftsmanship is still outa here
2:57 "Through capillary action it just SCHLUUUURRP..." haha this had me dying.
that's the scientific term
You've been well schooled. Great work and info!
I've built two frames with lugs. Silver brazed. It's slow, but the look is beautiful and you can customize a lot.
Alhamdulillah.. Brother you are the young star of cycle master technology.. I am appreciate your creative activities... May Allah / God bless you
For a novice like me, you nailed it thank you
I really enjoy your videos. There are couple other advantages that TIG has over brazing that you didn't mention. The first one is that TIG arguably produces a stronger frame because the heat affected zone of the joint is much less. The TIG torch produces rifle like accuracy whereas the brazing torch has more of a shotgun like effect spreading heat into a much larger area. Secondly, all things being equal, the frame that is TIG welded will be lighter than the frame that is brazed as the TIG joints will have less filler material in the completed joint. Keep up the good work Joe.
Yes, but also no. I think that TIG (fillet) brazing takes the cake here. The problem with actually welding highly alloyed tubes like these is that when you make a puddle with the base metal you are actually pulling the alloying elements to one place and you are creating a brittle zone there. That is why any weld will always fail and crack right next to the weld. From a metallurgical standpoint welding alloys is a shitstorm. TIG brazing will keep the basemetal the coolest and strongest at the expense of a few extra grams of bronze per frame. We are talking about maybe 30-40g of bronze per frame after the fillets have been filed compared to 10-20g of steel filler wire if TIG welding.
At 3;00 you showed hard copper pipe. I have successfully welded the fittings of this type of metal, using copper rod and Oxi/Acet. John Chaplain's comment is valid. Torch welding steel is a beautiful thing. Over TIG, you have more control because of the lower temp. and the puddle is really thick (not runny) so there's plenty of time to pull the puddle around and get superb penetration.
I agree 100%
Exactly my words as I was thinking it you was saying it. Soldering / Brazing even with the plumbers example exactly my thoughts. I'd never fillet braze not enough surface area for my liking.
I don't think that the amount of material in the brazed joint adds much to the strength. In fact, I think you'll find that the less braze there is in the joint (ie the closer the sliding fit), the stronger it is. The fillet is there to spread the stresses.
As I recall, the molten braze diffuses into the parent metal and forms a microscopically thin intermetallic crystalline alloy at the surface. The joint isn't "glued" (like a joint in wood, for example) but the metals are joined on the atomic level.
I'm starting to get into brazing and so far I found I really love using a propane torch and silver filler.
I don't need to mess around with acetylene and the silver makes such beautiful clean small fillets with barely any post processing.
I really wanna see if I can build full frames with this.
If I can get the prep work to fit the tubes nicely quick enough I think the price of the filler can be offset by how quickly it brazes into a nice little fillet
I am old. I braze everything. I don’t do aluminum, but they do make aluminum brazing rods for the HVAC industry and others, however it’s very difficult and I have no idea if it would work for bicycles. I have tried it on scrap lawn furniture as an experiment. If it can be done reliably and consistently it’s very difficult. You would need a very good system figured out and lots of practice. Not worth it. The aluminum is hard to read. It will melt long before it would glow red. You really have to braze with an air tip at the most. It just turns to butter under a torch. It’s very hard to repair a melt through. Great info and video.
When I was cycling seriously back in the late 70s and early 80s, the concern was always overheating and damaging the tubes. This was in the days of Reynolds 531, 753 from England, Columbus from Italy, Vitus from France and Ishiwata and maybe Tange from Japan.
I seem to recall you needed a license or certification to make 753 frames because they were very delicate. I would guess that once TIG welding came along, tube development has occurred to allow for use of the process without compromising the characteristics of the tubes. Back then, braze-ons were frowned upon in the UK ( Italian bikes had them everywhere ) and chroming was discouraged, again because of potential damage to frame integrity.
My impression is that you can silver braze anything as long as you don't overheat but I wonder about TIG welding. Just checked the Reynolds site and they pretty much seem to be saying that they made their newer products TIG friendly.
1) What state is your shop in? 2) How much would you estimate it would cost a noob to procure a quality Brazing and TIG rig? 3) Kindly list your estimate$ of each and brand preferences. 4) Do you use BikeCad or another 3D CAD modeling software? Thank you for such articulate, inspiring, and imformative videos. Have a wonderful Holiday season,phil
1:19 I haven’t touched a acy-oxy torch in 50 years but that is a damn good bead!
Great video & nice shop. I'm trying to learn to braze.
Very impressed with your knowledge for being so young. What many are missing though, is inline liquid flux. If you are welding frames more than once you should be using it. I used to braze bike's and wheel chairs in a production environment, and you can fly when brazing, with minimal clean up. I also Tig welded for all kinds of frames. Both like you state have pros and cons. Man, I can't imagine how much you will know in ten years from now. Try the inline flux, you will laugh that people still use paste. You can braze faster, cleaner and have more control over where the brass goes. Of course the tip size is also a factor along with how quickly you can move. Skill level is the most important factor, but it come down to practice like anything else.
Is silver filler typically used for lugged brazing and bronze is best for fillet brazing? Thanks. You are great teacher.
Really enjoying your videos, man. Do you do any rack fabrication? I've done frame brazing but it's been hard to find any info about fabricating racks. Tubing used, how to best bend tubing, etc.
I just might do a series on that!
Great video. Thanks for sharing.
great stuff - thanks!
Fillet brazing with a gas fluxer saves a lot of time on preparation and clean up.
Very good 😊 great job 😊
Does tig welding make for a stronger joint than brazing? You would think so if it actually melts the 2 components together, whereas brazing only melts the filler material to act as a glue. That's my interpretation of the two situations. Correct me if I'm wrong🤔
Hi I have a question. Can I fill a small crease in thin bicycle tube with silver solder and a simple propane torch that does not use acetylene? The tube is seat stay about 10 cm from the drop-outs.
Great video
Interesting. Thx!
Thanks Anthony Thintano
Thank you for clarification. 👏🏻
This was very helpful, thank you.
GasFlux process allows brazing without paste flux. No residue to clean off. It's much faster.
Just curious, why is your bender mounted to your mill? Love the Bridgeport btw, I have the same and love it.
Good stuff. In brazing you’re actually seeping in filler underneath the two materials to join them and get that semi-fillet curve going as you call it. It’s also way easy to go the other direction and glob too much filler and concave the braze round. That case lends the possibly to joint failure as you don’t know if the filler actually seeped and sealed the joint. Advantage to TIG, I think is even if you’re burning holes in joining materials you can cover them and ensure you’re getting a good bond. My two cents from trial and error and a certain school of thought. Thanks for posting.
I have to make a small repair to a brazed frame but I only have a mig. Will I destroy everything if I mig weld next to a brazed tube?
So could I braze an entire swingarm and frame to build an ebike? Or would the brazed joint be too weak and crack?
Cobra Framebuilding ? Do you have a store that sells custom made Ebike frames with full suspension ?
I was surprised you didn't mention one advantage of welding (including bronze welding) frames, which is that you're not restricted to the sizes and angles of available lugs. High-end TIG welded frames took off around the same time as mountain bikes, I suspect for this reason.
Hey there I have a question. I have an aluminium folding bike, and I want to add a better fitting basket on the front. It doesn't have mounts. I have considered drilling into the frame and adding a klickfix, or brazing a custom mount onto the front that I can slide a custom made basket into. What do you think? Better to to sand down a bit of the coating and braze, or better to drill and set a couple holes? Thanks. :)
The hexavalent chromium is no an issue when TIG welding stainless, only when MIG welding is it a problem. TIG welding stainless does expose you to ozone (small particles). Proper ventilation is the key here.
What are your thoughts on tack welding with TIG to get the alignment and then finishing with fillet brazing?
I have tried that once or twice, but once I really had my own TIG machine in my shop I stopped building bikes with fillet joints, so I never got that far into it. I have heard it works well, but I don't know who does it. I would talk to some of the fillet builders who also have TIG machines around -- they have all likely tried it.
Coming in late here but curious how bad would mig welding be for adding a disk bracket etc. to an old steel frame MTB?
It would be fine for a low-end steel frame but not for lightweight alloy steel tubing. For adding a disk mount you could probably use silver solder and a propane torch but you'd need to take a lot of care with the fit and cleanliness.
Great buddy👍👍👍👍that was very helpful
Can you repair a crack from the frame with welding?
RE: Old school brazing into the 80's and 90's- the advent to of steel alloys that air harden made the move the to the higher temperature process of welding workable for high-end bikes. Previously, tubing was heat treated from the factory, and the thinking was that brazing allowed better heat control and less risk of killing the temper on the tubes.
Reynolds 853 really did change things a lot- it was, to the best of my knowledge, the first premium bike tubing that was designed for welding (or, in some cases, high temperature brass brazing).
Thanks for that!
When Reynolds first came out with cold worked air hardening 631 and heat treated air hardening 853, Reynolds approved welding the thicker, softer 631 and only brazing the thinner, harder 853 tubing. Reynolds originally recommended against welding 853. When Reynolds later decided to approve welding of 853, I did start seeing welded 853 frames that had cracked. Is this due to being heat treated or is it due to the tubes being so thin? Most other tubing companies that sell air hardening tubing, sell in it only in the heat treated, hardened condition, so I think the welded 853 frames are cracking because the tubing is so thin and difficult to weld properly, because it is so thin. It is interesting that Reynolds originally recommended only brazing 853, while the thicker 631 was approved to be welded. Maybe they knew something all along. Other than the thicknesses of the tubing, the thicker 631 is not heat treated and the thinner 853 is heat treated. Is it thinner than other tubing companies' heat treated air hardening tubing? Reynolds has a chart with the hardnesses before and after brazing. High temperature brazing is recommended of the air hardening tubing. The 631 would become harder at the brazed joints and the 853 would become softer at the brazed joints, but the brazed 853 hardness was still higher than the brazed 631 hardness. I've seen too many welded 853 frames crack to recommend welding 853, but I do like air hardening tubing for bicycle frames. Maybe the other brands ren't hardened to as high a degree of hardness, or maybe their tubing is thicker and less prone to cracking when welded. The thicker, softer 631 doesn't seem to have the cracking problem when welded and other brands, which most all are heat treated, seem to weld alright. I think 853 survives best when brazed, but might be on the thin side for crack-free welding.
I came here to get some light on to why some mtb steel frames made in Taiwan are much more (we are talking 300-400USD) expensive (I think of Surly Krampus or Ritchey Ultra) than others also made in Taiwan (like Sobre Off or Nordest Britango). Are the expensive ones TIG welded and the cheaper ones done through a cheaper, less quality method? ALSO, some frames have only 1 gusset on the downtube other only on the toptubes, and apparently they are all regular 4130 double butted tubes. Does only 1 gusset make it cheaper and therefore more prone to braking the frame in the long run? I got excited and I asked too many and complicated things. I will understand if you ignore my message
I don't know what an LUG is, I don't know what an WATERBOTTLE is, Thanks for the video.
Mechanical design(?) Is it a poor decision to weld a bike frame & not re-jointing the brazed joints?
I need to ask you a question, I used to ride a re unbent trike, and a car hit me fractured the frame and eventually broke a part, so I’ve been looking for somebody to do so, but because of COVID it is hard to get somebody to do it, where are you at so perhaps you can’t take a look at it.
I thank you before hand and hope to hear from you
Carlos
In the 1970s I was a flame Brazier for Huffy bicycles so let me tell you how it was done son as soon as you picked up the torch off the economizer valve the gas came on allpria justed the flux was mixed in with the settling we use the number 5 tip with the valve for the settling crank all the way open the regulator's cranked up to the max then you would turn the oxygen up to you had a oxidizing Flame two welders could put out 60 frames an hour not counting for spot weld and the head to was done separately the wells got a visual inspection dipped in a cleaner and painted no cleanup at all it was all about speed speed speed baby because Huffy bike were cheap cheap cheap
Isn't brazing super expensive cos of the Oxy/Acet set up??
Oxy acetylene welding from my experience is the lowest cost way to weld or braze. Go price everything necessary for OA welding and look at the cost of a tig machine big cost difference.
Darn good video, thanks a lot!!!!
Heya! Great video. Have you guys tried brazing or welding Titanium frames?
Very good knowledge, are you tools available in the UK,
Very useful information, thank you. My frame recently cracked where the seat tube joins the bottom bracket. It is a steel frame from the early 1980s (Centurion Super LeMans), which I understand was made from "double butted" steel tubing. I was planning to take it to a welding shop for repair. Do you think TIG or brazing would be better? Thanks again.
Damn i have the exact same frame laying around. Rusty torn. Considering fixing it up! Nice frame
Good question. I know on motorcycle frames they always crack where the seat post joins at the bottom. Have you thought about stripping the paint or coating off the areas you are concerned about and having a shop Magnaflux that area and mark out see exactly where the crack starts and stops ? That is what I do when someone brings me a cracked frame I strip it down clean and magnuflux test that entire frame with my magnet and shaker of iron powder because I want to be able to go to bed knowing that frame will be safe.
The Dog : Boss, you're talking too much.. where's my meal.. 😰😰
I found an old Roadster Bicycle frame with a broken but brazed Bottom.
How strong enough could I assume the Bottom to be, compared to its original make ?
Appreciate an early reply !
Thank you !!
Why wouldn’t you be able to MIG weld frames?
I was wondering if TIG brazing could work too? What do you think of TIG welding it first and filling it up with SiB & TIG brazing (just for the nice look of it). I am welding in my basement and Oxy-Ace setup is just too dangerous there due to poor ventilation, still I TIG braze random stuff a lot for the sake of the fillet-brazed look. Thx in advance!
Can you stick weld a bicycle?
Kmart and Walmart bikes are TIG welded, or simply spot welded. Very uneven heat (6000 degrees), and poor frame tube adhesion (joining the frame tubes together) are the result. These kinds of bikes are produced in the masses, not quality. I’ve owned a few of these bikes, they’re junk. Brazing, on the other hand 🤚, is done at a WAY LOWER temperature (and even heat, too) 🤒, resulting in a VERY STRONG bicycle frame. Such a bicycle frame could last up to, and past 10 years, and is VERY WELL worth the investment. Your friend, Jeff.
What about brazing alloys?
Thanks for the info. I’m building a motorized bike with the standard kit mainly, if you’re familiar with that. I need to mount a gas tank onto the top horizontal bar of the frame on a men’s bike, thinking about brazing, any thoughts on that? Thanks in advance!
Edit: steel frame
Old motorcycle frames and the old springer front ends were furnace brazed together so you have brass inside of your tubes. Guys who modified old springer front ends making them longer using old ford radius rods brazed or welded them safely with oxy acetylene. The book I learned from for motorcycle frames is Custom Chopper Cookbook by Mike Geokan check it out he builds gorgeous frames for the street and for land speed racing. I am really glad I found your channel I really like your work and appreciate your sharing your knowledge.
Is that mill a Bridgeport ... ta
Hetchins were once asked by an American interviewer how long it takes to file their brazed fillet joints to that beautiful finish.
The very indignant answer was "We do not ever file our joints at all."
You had to say "American interviewer," like that was relevant.
What about strength, in term of frame durability?
which on stronger? Braze or Tig?
Whats the difference in strength of the build?
I need help. I have a fixie steel frame i think its chromoly and i already hammered the inner chainstay so i can fit ma wide tire. So here is my problem i want ti fit a 700c x 45 on it but it hits the inner chainstay. My solution is find someone that can cut and weld new rear triangle of the bike is that even possible and safe if it si
It's doable to replace the chainstays. It's probably not cost effective. Being happy with what you already have is going to be the cheapest. If you must absolutely have fatter tires getting a different frame usually makes more sense.
What about TIG brazing?
hi, great video, any thoughts on stick welding a bike frame?
hmm 6011 in 3/32, 1/16, fish mouth with a little space for the material of the electrode, i try with 6011(3/32, 1/16, 1/8), 6013(3/32), 7018(3/32), 7014(3/32), i fk smash with jumps and hammer the frames and don´t have any problems with the stick welding, tube of steel 1,5 mm to 2mm that work for me, i try repair a tange tube with stick welding and fking destroy the frame is a bad idea stick weld a thin tubes
peachcycles is a chilean guy who sell stick welding frame bike, look his instagram, his first post, he change the welding for hard brazing
I think it would take a lot of skill to stick weld a bicycle frame you’d have to turn the juice right down and just dab with the stick
And I think a 2 mm 6013 rod would be your best chance of doing it
I'll just take "brazed" wings for now 😄
Great piece of advice! Would MIG welding be inferior in any way with a slightly thicker steel frame material?
Well, I think generally you’d need pretty thick tubing for MIG to work well. Thick tubing makes really heavy bikes, which are fine I guess, but man I don’t want to ride a 40 pound bike. If I’m going to the trouble to make I by hand I want to make it NICE.
why not tig braze? thanks for answering btw ;D
What CNC mill is that in the background? Looks like a HAAS minimill that was converted to Linux or something????
1996 Bridgeport Torq Cut 22. Good machine. Loud as hell.
Hey thank you so much! Is there any way to make lugs without machining them on the mill or buying presized ones? My dimensions are a little abnormal and I'd like to reinforce my joints with a basic lug of maybe just slightly larger pipe
You can make your own for sure. You need tubing that has the right slip fit over the inner tubing size. In USA if you buy the outside tubing 1/8” larger in diameter with a .058” wall it will have a nice slip fit over. So if you have a 1 1/8” tube and want nice sleeve material the easy way is to get 1 1/4” tubing with a .058” wall. .058” wall is kinda chunky so you still might want to turn that diameter down on a lathe if you have the means.
Watch some CS Hirose videos here on TH-cam -- he fabricates custom lugs for a few of his frames.
Which tig machine do you recommend?
you can braze aluminum. Its actually quite strong. Otherwise, a fantastic video.
I don't know too much about brazing aluminum, but my understanding is that it is not actually practical for frame construction outside of cable guides and small bits.
with the water bottle boss why not use rivet nuts
What about Tig brazing
Ever try "TIG brazing" with silicon bronze? It's a real thing, and apparently a significantly lower skill than "real" TIG welding (which I suck at).
What about a clean crack in the frame?
How about TIG brazing?
Good for making use of aluminum or silicon bronze.
Thanks for the video! Can I use propane + oxygen instead?
Yes
For braising
Good work.
Dog adds cred, what is their name?
First time I've heard solder pronounced without the L. Apparently thats a known thing 😉
Clementine Puppypaws
That Everlast tho
I was able to get my hands on some stainless tubing for cheap. It’s about 1.5” OD 035 wall. Not sure what type of stainless. Question is, can I braze a frame together with it? I brazed a 4130 frame years ago, so think I can do again, but don’t want to buy a torch if I can’t use on the stainless. Guy at weld shop says SS can’t be brazed, but wonder if that doesn’t apply to bikes where metal mass if very small and therefore maybe can get hot enough. Thoughts?
"wonder if that doesn’t apply to bikes where metal mass if very small and therefore maybe can get hot enough"
Repeat this to guy at weld shop and see what he says.
Cedric What are you saying? His opinion was pretty firm. Was hoping someone on here has tried it before.
Chris Mason people do braze stainless even though manufacturers don't generally recommend it. However, they seem to be O.K with brazing when using lugged construction. As you don't know the alloy I wouldn't try brazing it without lugs. Look at silver soldering it too, that'll keep the heat down.
Anonomosomous appreciate the comment. Lugged brazing is more for the classic bike design and method. The one frame that made was brass fillet brazed (not lugged). It was on 4130 and lasted over a decade with a lot of abuse. Wondering if there’s some reason this won’t work on SS. I think I’ll just have to make samples and test to destruction. Thanks again
I'm not sure why he said SS can't be brazed, because it can be. Now everyone here seems to be talking about brazing with a torch, and mostly sweating connections and maybe that is where the trouble is? I have and many others have TIG brazed SS with out issues. You can get away with out having to purge. Some stainless welds badly so without knowing what you got...
Maybe braze or tig weld a tripod so your camera isn't shaking the entire time.
U r amazing
😁👍💗
8:51 its easier to clean off the flux when you don't use WAY more than you needed.
will you mentor me
Doesn't good TIG need 220V power?
In the old school you had "transformer" welders that were the size of a fridge and they used a lot of current so they were always 220v single phase or even 440v or three phase. Since "inverter" welders have become common there are a lot of options that will operate on 110v. They don't always have as much output when you run them on 110v, but they generally have plenty for welding thin wall bike tubing. My Everlast welder is this style. Also, wiring a 220v outlet is generally a pretty approachable DIY project and there are a bunch of youtube videos about that topic.
Kind of "what he said". Inverter TIG welders can do about 140 amps on 120V and that is enough to weld up to about 1/4", so much thicker than anything you are likely to deal with on a bike. Also many of them are dual voltage and can run of either, you just get more amperage available on 220V.
@@skoue4165 I used to TIG weld constructions from 1" and 2 3/4" with 1/8" wall aluminium tubes. The welder was usually set to 190-220 amps.
Anything lower would just take way too long although I started off at 140 amps until I got better at it.
@@cobraframebuilding if you getting 220VAC then there is something wrong with the wiring or the transformer outside supplying power too the electrical meter because the nominal standard in the USA is 120VAC and only allows for a range of −5% to +5% RMS. Note: The 240Vac is two legs so its 120+120.
Need change out my old 1” head tube put to have a new 1 1/8” head tube. Is it possible?
Any frame can be modified just take your time and fitting it up, measure, check, and see if it works. I have no college education all I have is learning from my father at a very young age, my own projects, job sites, figuring out what works, and what doesn't work. The best framework starts with that one question will this modification work ? The person builds something that works or learns how to make it work even better than expected. Best wishes and good luck 👍
When I was a kid in the '80s I was reading a book about road bicycles at the library and the author turned his nose up at welded frames, claiming they were inferior to his beloved lugged & brazed frames, and only found on cheap department store bikes. I knew he was full of shit because all BMX frames, including top-of-the-line ones, were (and are) welded, and they have to be a lot stronger than a road bike frame, considering that they have to handle big jumps. Mountain bikes were just becoming a thing at the time, and their frames are typically welded too. They also have to be stronger than a road bike frame, for obvious reasons. If he's still alive I wonder what he thinks about it now that even high-end road bikes have welded frames with no lugs.
Once upon a time the highest quality best regarded tubing for bike frames was Reynolds 531. Reynolds 531 lost a lot of strength with the higher heat from welding vs brazing. Reynolds 531 used a manganese steel alloy with strength as well as most other properties comparable to 4130 cromo except it's ability to withstand higher temperatures associated with welding. The bike industry found that welded bikes were cheaper to make than brazed (fillet or lug). Thus welded steel took over. Welded steel was eventually found to make a stronger joint than brazed (although good examples of each are both excellent).