A great video! Thanks for taking the time to share this with us. Here are some ideas I hope you find helpful. 1) To eliminate the cosmetic surface bubbles you can paint the mold with a coating of straight epoxy first. You could also color this epoxy to form a "gel coat" effect. Let it set up, or gel, before poring in the rest of the epoxy. If it isn't set enough, the epoxy granite mixture will "wash" it off. If it gets too hard it won't bond chemically with the epoxy granite and may flake off later. 2) De-gas the epoxy sand mixture in the bucket with your vacuum. That would help get rid of all of the little bubbles. Then be careful when you fill your mold to not create too many new bubbles. The bubbles you make pouring the epoxy into the mold will be large and those will rise to the surface quickly. 3) Packing ratio. Others have mentioned this. If you want to reduce the percentage of epoxy, you need to have different sized particles in your solids. If they are all the same size you will have a packing ratio of only about 64%. Mixing together sands of different grain sizes can increase you packing ratio and decrease your epoxy usage. 4) Epoxy does not bond to polyethylene. You can make your mold out of polyethylene as it machines nicely. There is also poly tape that can be used to to make a non-stick surface. Wax is still a good idea, but if you miss a spot it wouldn't matter much. 5) Sand blasting your aluminum parts is the gold standard for getting good adhesion with epoxy. Do it shortly before casting to prevent the aluminum from having time to grow a new oxide layer, and wear gloves to prevent contaminating the surface with skin oils. 6) Gloves: Wear them whenever you are using epoxy. Look up "epoxy contact dermatitis" to see why it is important.
you probably dont give a shit but does someone know of a tool to get back into an instagram account..? I stupidly lost the password. I would love any help you can offer me
@Declan Thaddeus I really appreciate your reply. I got to the site thru google and Im waiting for the hacking stuff atm. Seems to take a while so I will reply here later with my results.
Very. Cool. Game. Changer. This also solves the problem of the DIY guy who wants to make huge machine tool frames but has no access to iron casting equipment. Awesome project and video. Added to many of my playlists. But also added to personal favorites.
Super, super, super idea! I'm gonna build a mold for my 1k x 1k cnc router. You've opened my creative mind to endless structural possibilities with this option. What about welding a rebar reinforced inner structure, along with the aggregate/epoxy mix? You could do smaller pours and let set. You could pour a whole table, layers at a time and finish off with mounting options to secure your rails to or whatever your machine desires to function. Rebar is cheap. You could also integrate fence posts for structural support and not have alot of money in it. This idea has so much potential! Thank you for this video!
A welded rebar internal structure would work great! I've never tried the multiple pour option, but I don't see why it wouldn't work. The epoxy will bond to itself without issue between pours
First off great video. Very informative. I worked on an R&D project using Metal Injection Molding. The goal was to maximize the density of the metal balls and minimize the plastic filler. I learned that if you have fairly uniform diameter balls, the amount of plastic was about 17% (by volume) to have a mixture that had no interstitial voids with the minimum plastic. This 17% figure will always be the same for any mixture using uniform ball (or rocks here) size regardless of the size. Somewhat counter-intuitive to me. This would seem to be applicable if you assume that the sand grains are fairly uniform in size. You can get a denser mixture by using significantly larger rocks with the sand filling the space between the rocks. Here in Florida, I would put the fillers in the oven to drive out any moisture.
My internal dialogue: that looks so slick, need to do that as base for my 3D printer. Imagining wife’s question: why did you do that, you can’t even lift it? Me: Ummm. Doesn’t it look great?
If you use a printer that doesn't move the bed, you can make a heated bed using an aluminum plate and some underfloor heating elements, then pour the epoxy over it.
@@Krmpfpks the appearance is awesome right? Also works great for speakers since it's heavy and acoustically inert, raises the WAF by quite a bit in my experience.
I used to work making cultured marble and granit. We used powder and resins. Mixed it for about 2 hours, added dye, and laid it on a glass top shaker table. We shook it over night. Very informative though, as I'm wanting to build my own machine with a 4th axis for vertical round grinding, vertical free turn, and of course as a mill.
Chronicblazer... prolly pipe dreams from the account. Name. I had a guy tell me he was looking to.buy a UMC-750 for his garage. Yea bud I've got a McLaren F1 on pre-order
I think I've read your article on this about 10 times now. Great to see some videos too. A long-term review of the microscope / base would be interesting. Will keep watching for more videos.
WOW! That's just one of the best explaining videos I've ever seen! If not THE BEST! Thank you so much for your great scientific work and for sharing it with everyone! Just great. Cheers mate!
Returning to this video for more insight / inspiration. The quick links to different sections of the video is a winner. Definitely implementing that. Thanks again.
Super friend you posted most useful videos for solid machine base this process is very useful to mould any type of shapes and also no need to melting cast iron process also shaping metals right 🙏i appreciate and support your ideas, skills , hardwork because i know machine base body making is very tough jobs
Great work here! You inspired me to think of a couple things that might help. 1) a cheap shaker motor is easy to make: just use any motor, bur on the shaft you put an imbalanced load. 2) Instead of using an impossibly big vacuum tank, use the atmosphere itself by doing the opposite: mix the epoxy inside a pressure tank. That's way smaller. When you're done mixing releasing the air bubbles that were at high pressure should vent off easily into 1 atmosphere. When you pour it take care to not create bubbles. They shaker table should help with the rest of any trapped air.
Thank you for the deep explanations. The use of rocks has an issue, that the surface of the rocks you used is very rough. So air can stay at the Rocks. Classic concrete has stones out of the river, they are round to eliptic and can withstand high pressure. The amount of air stuck at the rocks is smaller. And this rocks are very cheap and you can use less epoxy. Good for bigger projects.
Thanks for this video. I've built a small vertical mill from aluminum, and the poor edge finish on cuts due to vibration is a real shame. This seems like a great approach for a small scale CNC mill
In our plant we have two Hardinage CNC lathe that machine metals to 0.0001” tolerance the beds are made from epoxy granite. Good material. Your machine looks like it would be very strong and stiff. I like your explanation on modulus and dampening.
Outstanding information, thank you. I now have the knowledge to make a proper base for my audio turntable (yes, I still play and prefer vinyl records) and my 3D printer.
Using a better mixture of quartz aggregates from 3/8" to flour allows the resin mix to be only 8%, which reduces cost and greatly improves the mechanical properties
Hello Adam! Good choice for the base but I was more interested in the precision aluminium sections and how you went about procuring them. Perhaps you could try the electro magnetic vibrator ( without a motor and eccentric weights ), which have a small amplitude of vibration about 1.6 mm, also used by construction people. Also you could use silica flour as fines. This and the sand should be dry as the heat generated will release some steam. Anyway you've been acquiring the skills as you went along. Best wishes!
This takes it to that next level. With this technique, it would be interesting if applied to a desktop lathe either hybrid or one off. They do suffer vibrations something fierce. Great build and presentation!
Nitpick: your design criteria was all about the material science of epoxy granite but my layman's assessment of your prototyping was what looked/poured best. While air gaps are probably not great, how can you know if some ratio with air bubbles might be much better than what you went with in the end? You didn't test the characteristics you chose it for via any means I saw: vibration resistance and stiffness. Thoughts?
A bit harsh perhaps, but I agree. The design aims are mixed up. If impeccable surface finish is important then use a gel coat or post process in the old fashioned way with filler and sanding. If a very specific mix of rigidity and vibrational damping is top priority, then they are mutually contradictory. A rigid material does not damp; a damping material cannot be rigid. There was no evaluation of the result.
@@raykent3211 Whoops. Didn't mean to be harsh, just objective! There was a lot of background given on the material choice and explaining the challenging blend of properties you mention: rigidity and damping. I guess I interpreted this as a technical focus, so it surprised me that none of the introduction material came back up during evaluation. That's all. Maybe it's sufficient to say "this material was known a priori to be great and thus as long as we use it, all that matters is the practical aspect of forming it well and having it smooth." Like if "wood" had the right property, then perhaps that's sufficient and an evaluation between maple, walnut, or pine don't matter. Dunno, but wondered the author's thoughts.
@@johnhendy1281 it's certainly an intriguing subject and not easy! My only reference is acoustic damping. The key seems to be near-continuous impedance variation. Realistically, the sound hits a low impedance (not stiff) material to avoid reflection and progresses through layers of increasing stiffness ending with maybe concrete. It's a matter of absorbing energy and minimizing reflection and propagation. But the energy can only be absorbed if the source is allowed to move, which for many machines is bad. I doubt if anyone would want a cnc spindle mounted in anything less than a perfectly rigid way.
@@raykent3211 With machines, there is already high impulse vibration in the metal. This is a bit unlike acoustic damping, where you need to pull the vibrations out of the less dense air and have to progressively absorb into more dense materials. The alu will carry the vibrations (usually unfortunately well). So by casting around the alu, the alu becomes a carrier to transfer to the absorber. This works similarly well with filling box beams. Though their outer surface can still carry some vibrations. If you imagine them trying to resonate, the semi-squish and mass of the super absorber material eats up all the inward pulses. That makes it extremely good at sapping any harmonics from growing.
Maybe I am assuming things incorrectly, but reducing air bubbles/pockets maximizes the density of the base, therefore adding more mass to lessen the vibrations. He most likely could just get away with having some air bubbles but if the final mixture can have better density and requires less variety of materials, it would simply be better to use the chosen material composition. And perhaps (could be really wrong) in extreme cases where excess vibrations are transmitted to the granite base, the pockets could act as stress risers potentially creating failure points, thus propagating cracks.
I just watched a special on submarines and carbon black as a dye adds to sound and vibration deadening by multitudes very interestingly I'll be using it if I try that that's actually why submarines are black even though blue would be better so as no to be seen and a palm sander on its side vibrates the bubbles out just fine vibrating it along the sides of mold
Some suggestions: 1. To improve mechanical characteristics, use - a single digit percentage of epoxy - an aggregate with significantly better packing density - preferably grey cast iron or at least steel as reinforcing and interface members as its CTE matches that of the composite described above
2. Feel free to coat the inside of the mold w/ your material of choice (most of the time I use carbon-filled (i.e. toner powder) epoxy which gives a nice, shiny, smooth, jet black surface) before you start filling the mold w/ your actual mix. This way you don't have to factor in aesthetics even when you're supposed to design your composite to achieve the best mechanical properties. 3. Reinforcement might not even be necessary at all if your machine frame was designed to take advantage of the compressive strength of the composite, which can be brought up to 200+ MPa if you're open to using a more decent mix. Machine tool manufacturers don't seem to bother reinforcing their frames. 4. Vibration is the way to go. Vacuum pumps don't take epoxy vapor particularly well.
If you arrange internal cooling to the aluminum frame, it is actually better than steel or cast iron, as it conducts heat 3 times faster, thus you are able to maintain a set temperature easily.
being careful not to mix in air when mixing will help. Mixing larger batches so your paddle mixer can be kept below the surface. great video, subscribed!
A few of my ideas... step 1 mix just clear expoy and harder together brush spray into mold... let it tack up the us a heat gun to pop bubbles... on the surface of mold let it set up for several hours.. Step 2 mix epoxy with harder and black pigment or paint... spray over the clear expoy let it tack and use heat gun to pop bubbles repeat a few times on corners or vertical surfaces where you need thicker covage...let it dry or tack almost dry.. Step 3.. mix expoy part a b add optional dye then add sand.... the harder... apply with spreader or bondo spreader to mold 1/4 to 1/2 thick coat as a surface finish to finished faces.. let it dry Step4 next day mix expoy with sand and some small gravel...fill mold up to 1/ 4 below desired depth...mix new top coat with expoy sand mix and Harder etc... to give smoother finish on under side This is how I get flawless smooth expoy granite.
Great video! I'm planning on reinforcing and expanding my small milling machines column and base and make the switch to linear rails on all 3 axis. This information is very helpful.
He did a good job, but is using way too much resin. It will provide poor mechanical properties.CASTINITE
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Hey Adam, such a great addition to your page that, like so many other, I have read tens of times, which have spread the knowledge, experience and inspiration for this amazing technique. Thank you so much for sharing 🙏🙏🙏
Outstanding content. In 2 part polymers with fillers, I have always been told you need to mix part a and b together then mix in the filler to prevent differential adsorption of one part in the filler (sand in your case) which would inhibit a full cure. You're method seems nice since you're not rushed by the curing epoxy during mixing. Did you notice any softness in the end product?
Might I suggest drying the sand by baking it in a oven for a while in my limited experience with resin and fillers moisture in the filler really messes with strength and leaves tiny bubbles in the material due to a chemical reaction.
I am thinking about using Aluminium oxide, but I am not sure if the epoxy will be able to bond on it, considering a welding require to break the oxide layer prior to have a good bonding.But then since epoxy stick with pretty much anything, I hope it could be an option.
@@CozzyKnowsBest Hey thanks, I was just under impression that aluminium oxide would be best, but figured out it might be a piece of mind to go straight for your reccomended products. Currently I have 30kg of play sand that also lays around in the house for a while. I might give it also a try like Adam did. Though I am looking for Epoxy seller around Montreal, will be the toughest part.
I have been looking for this for a long time now. Thank you 1000 times. I just finished a steel gantry mill and it vibrates worse than a tuning fork and i need a solution. This is it. I'm going to fill it and encase it with epoxy granite. lets see it run!! Best Matt
Yup! This would be a great way to do it! Another option if you have a tube framed design is to fill the tubes with sand! Sand does a great job at killing vibrations too. Just be careful, it'll make things white heavy! Make sure you have enough power to move your gantry around
My theory: using a vacuum chamber or high pressure to get the bubbles out will propably lead to maybe only epoxy filling the voids. You want the filler material as dense as possible though. Vibrating the material would be the best choice then I think. Your vibrator table seems to not be sufficient enough, maybe try a small electric motor with an offcenter weight on the shaft, and something to control the motor speed maybe. Would also be cheaper. Only using sand is also not that great, since it still is kinda coarse. There's some basalt based grit that's used for filling the gaps between walkway stones, it has bigger particles (maybe 1/16") down to dust like particles. Should work nicely.
Nice video! Clearly and logically presented. A few questions. Have you thought of introducing aggregate into the mold as you have a base of epoxy and sand mix in it. In other words use the aggregate as a filler. As you have the vibrating table working the aggregate will sink into the mix quite easily. Second thought. As you have shown that you have access to a vacuum pump how about simply making a vacuum bag out of window setting tape and heavy polyethylene house vapour barrier? Connecting supplies in the form of bag to hose are available in a few places. The pump will only draw the air out of your bag. Your test sample that foamed up most likely never had an actual vacuum drawn but was in a leaking chamber. When I'm doing vacuum veneering I generally use a shop vac to evacuate the bulk of the air and even a small shop vac can create a quite useful vacuum. Useful enough that pretty much anybody that can fold up a heavy plastic bag can get this accomplished. In a pinch good quality duct tape can be used to create and seal up a polyethylene bag.
Filling the mold first will not work as the epoxy will not properly coat the aggregate. With a proper filler mix, which would include larger aggregate, the air cannot be drawn out using a vacuum.
Are plans for the rest of the CNC machine available? Also, I wonder if you could further reduce vibration by filling the hollow aluminum tubes with additional vibration dampening material.
Just curios, why not use steel or aluminum as the mold and final base with the epoxy granite on the inside? Would this not provide the stiffness of steel and the epoxy granite vibration absorption? I am not a engineer, just curious if there would be any reasons why this would not be a good approach.
of course you can do that it just wouldn't look as stylish. is there any reason to not have the epoxy granite as a show piece while providing vibration dampening?
After days of research on epoxy floors, I ended up trying the most convenient supply epoxy for samples: my employer's deadstock of ENECON DURAFILL. It filled and leveled my old wood floor perfectly, with no bubbles or nonsense. Too bad it costs $300/gal, but all it takes is one failed pour to lose more, and it really is hard like glass, chem and UV resistant.
Excellent work young man. I am impressed. If you are a college educated Engineer, then I am really impressed as most of them, I have worked with, couldn't find their rear end with a map and both hands.
I have done this with my own recipes and here are some tips and tricks. 1) Pre-heat the sand and resin which helps to speed up curing and removing bubbles as it lowers the viscosity of the resin. ( I didn't get any bubbles without using a vacuum chamber) 2) I mix sand, pea gravel, and crushed rock for mine as it uses less resin (Approx 5-10% resin to other ingredients) 3) Fiberglass resin also works extremely well and this is what I use (40$ at Walmart for a gallon). 4) If you want it to look professional, mix in charcoal powder to give it an extremely black coloring and nice surface finish. I made my powder from aquarium charcoal in a blender. For my next tests, I will be mixing glass fiber along with the other ingredients to try and increase the composite strength. I was blown away by this polymer concrete's performance and will not be going back to regular concrete.
I was able to drill the material pretty easily (for internal wiring) with a concrete bit, but I never tried machining it. I would imagine the sand would destroy the end mill pretty quickly, but it might work for a bit? Better to embed aluminum or steel in the material where you want to machine, and machine the metal after it cures.
Great video. Just one small point. It may seem obvious, but you should have emphasised that the mould should be levelled very carfully before pouring the mix.
You can only drill it. Maybe surface grinding works to, but I've never seen that. Thats why you put aluminum or usually steel plates on the functional surfaces like shown in the video. Some people mold some long nuts into the casting, to get deep threads.
You can definitely drill it with a drill bit meant for concrete. I have done so a few times to pull wires internally through the frame. It drilled without any issue. I did not try milling or grinding it.
So when it comes to vibration dampening, did anyone ever compare this to the stuff typically used for setting machinery? Stuff like precision grout, or some of the metal based aggregate grouts, or something totally epoxy based like Loctite nordbak? I would be curious how an epoxy and precision grout would behave. Interesting, would be cool to see some data on vibration dampening effect.
I started the first polymer concrete casting company in the US in 1988 and have been producing castings for grinding machines, inspection equipment, chip bonders, chemical pump bases, etc, since. CASTINTE
Nice work! I was thinking cast the base from Portland cement mortar, then paint it with dyed epoxy resin, or another type of resin. It would be cheaper and do the same thing. I don't know if you could make it look as good.
For epoxy selection maybe try using a deep pour epoxy? Not sure how it would effect your tests, but it has a far longer cure time that what you were using. 3 days to cure. There are some epoxy out there that cure even slower
I want to make a slightly larger gantry mill but I'm curious instead of using aluminum stock bolted together can you cast the aluminum I would imagine the joints would be much stronger but does the aluminum have to go through some sort of hardening process to make the material stronger? this could be a much cheaper and potentially stronger option if done correctly but gaps in my knowledge is setting me back lol 😹
I moved onto other projects and things in life. But I thought I'd share the process I learned so others can build on top of it, and keep making it better. Thanks for watching
A great video! Thanks for taking the time to share this with us. Here are some ideas I hope you find helpful.
1) To eliminate the cosmetic surface bubbles you can paint the mold with a coating of straight epoxy first. You could also color this epoxy to form a "gel coat" effect. Let it set up, or gel, before poring in the rest of the epoxy. If it isn't set enough, the epoxy granite mixture will "wash" it off. If it gets too hard it won't bond chemically with the epoxy granite and may flake off later.
2) De-gas the epoxy sand mixture in the bucket with your vacuum. That would help get rid of all of the little bubbles. Then be careful when you fill your mold to not create too many new bubbles. The bubbles you make pouring the epoxy into the mold will be large and those will rise to the surface quickly.
3) Packing ratio. Others have mentioned this. If you want to reduce the percentage of epoxy, you need to have different sized particles in your solids. If they are all the same size you will have a packing ratio of only about 64%. Mixing together sands of different grain sizes can increase you packing ratio and decrease your epoxy usage.
4) Epoxy does not bond to polyethylene. You can make your mold out of polyethylene as it machines nicely. There is also poly tape that can be used to to make a non-stick surface. Wax is still a good idea, but if you miss a spot it wouldn't matter much.
5) Sand blasting your aluminum parts is the gold standard for getting good adhesion with epoxy. Do it shortly before casting to prevent the aluminum from having time to grow a new oxide layer, and wear gloves to prevent contaminating the surface with skin oils.
6) Gloves: Wear them whenever you are using epoxy. Look up "epoxy contact dermatitis" to see why it is important.
Replied because simply clicking a thumbs up doesn't do this comment justice. Good post JH. Should be up there, right at the top ^^^^^^^^^
you probably dont give a shit but does someone know of a tool to get back into an instagram account..?
I stupidly lost the password. I would love any help you can offer me
@Declan Thaddeus I really appreciate your reply. I got to the site thru google and Im waiting for the hacking stuff atm.
Seems to take a while so I will reply here later with my results.
@Declan Thaddeus It did the trick and I actually got access to my account again. I'm so happy:D
Thanks so much, you saved my account !
@Tyson Neil You are welcome xD
4 years later and still super useful. Thanks!
More,more,more,please. Fantastic build and awsome video. Thank you for your generosity.
Very. Cool. Game. Changer. This also solves the problem of the DIY guy who wants to make huge machine tool frames but has no access to iron casting equipment. Awesome project and video. Added to many of my playlists. But also added to personal favorites.
••• Goes to garage to begin casting 8'-0" tall English wheel. •••
Super, super, super idea! I'm gonna build a mold for my 1k x 1k cnc router. You've opened my creative mind to endless structural possibilities with this option.
What about welding a rebar reinforced inner structure, along with the aggregate/epoxy mix? You could do smaller pours and let set. You could pour a whole table, layers at a time and finish off with mounting options to secure your rails to or whatever your machine desires to function. Rebar is cheap. You could also integrate fence posts for structural support and not have alot of money in it.
This idea has so much potential!
Thank you for this video!
A welded rebar internal structure would work great! I've never tried the multiple pour option, but I don't see why it wouldn't work. The epoxy will bond to itself without issue between pours
This is the only video I have ever given a thumbs up. People should be required to watch this prior to uploading instructional videos. Thanks man.
First off great video. Very informative.
I worked on an R&D project using Metal Injection Molding. The goal was to maximize the density of the metal balls and minimize the plastic filler. I learned that if you have fairly uniform diameter balls, the amount of plastic was about 17% (by volume) to have a mixture that had no interstitial voids with the minimum plastic. This 17% figure will always be the same for any mixture using uniform ball (or rocks here) size regardless of the size. Somewhat counter-intuitive to me. This would seem to be applicable if you assume that the sand grains are fairly uniform in size.
You can get a denser mixture by using significantly larger rocks with the sand filling the space between the rocks.
Here in Florida, I would put the fillers in the oven to drive out any moisture.
that's because of the nature of packing spheres. Sand grains can pack much tighter because they aren't spheres.
At the start: "TH-cam, why are you recommending this?"
By the end: "My 3D printers are gonna be really heavy in about a week."
Haha, can't wait to see the ultra beefed up 3D printer
I thought the same ahahaha
My internal dialogue: that looks so slick, need to do that as base for my 3D printer. Imagining wife’s question: why did you do that, you can’t even lift it? Me: Ummm. Doesn’t it look great?
If you use a printer that doesn't move the bed, you can make a heated bed using an aluminum plate and some underfloor heating elements, then pour the epoxy over it.
@@Krmpfpks the appearance is awesome right? Also works great for speakers since it's heavy and acoustically inert, raises the WAF by quite a bit in my experience.
I used to work making cultured marble and granit. We used powder and resins. Mixed it for about 2 hours, added dye, and laid it on a glass top shaker table. We shook it over night. Very informative though, as I'm wanting to build my own machine with a 4th axis for vertical round grinding, vertical free turn, and of course as a mill.
You ever get started on this?
Chronicblazer... prolly pipe dreams from the account. Name. I had a guy tell me he was looking to.buy a UMC-750 for his garage. Yea bud I've got a McLaren F1 on pre-order
I think I've read your article on this about 10 times now. Great to see some videos too. A long-term review of the microscope / base would be interesting. Will keep watching for more videos.
Thanks for watching Aaron! I'll keep the videos coming.
@@AdamBenderwhy not adding fine rubber or foam aggregate with concrete and a urethane binder? Why aluminum not steel?
Your finished product is a work of art.
This is my favorite video to be honest was so excited to see more of it please do a update of sorts
WOW!
That's just one of the best explaining videos I've ever seen! If not THE BEST!
Thank you so much for your great scientific work and for sharing it with everyone!
Just great. Cheers mate!
Returning to this video for more insight / inspiration. The quick links to different sections of the video is a winner. Definitely implementing that. Thanks again.
Super friend you posted most useful videos for solid machine base this process is very useful to mould any type of shapes and also no need to melting cast iron process also shaping metals right 🙏i appreciate and support your ideas, skills , hardwork because i know machine base body making is very tough jobs
Great work here!
You inspired me to think of a couple things that might help.
1) a cheap shaker motor is easy to make: just use any motor, bur on the shaft you put an imbalanced load.
2) Instead of using an impossibly big vacuum tank, use the atmosphere itself by doing the opposite: mix the epoxy inside a pressure tank. That's way smaller.
When you're done mixing releasing the air bubbles that were at high pressure should vent off easily into 1 atmosphere. When you pour it take care to not create bubbles. They shaker table should help with the rest of any trapped air.
Thank you for the deep explanations. The use of rocks has an issue, that the surface of the rocks you used is very rough. So air can stay at the Rocks. Classic concrete has stones out of the river, they are round to eliptic and can withstand high pressure. The amount of air stuck at the rocks is smaller. And this rocks are very cheap and you can use less epoxy. Good for bigger projects.
Pea gravel...
Thank you Adam for this very intresting video.
Thanks for this video. I've built a small vertical mill from aluminum, and the poor edge finish on cuts due to vibration is a real shame. This seems like a great approach for a small scale CNC mill
Thank you very much for sharing your work. You have put lot of time and effort to educate people like me. Keep up your good work. Good luck.
In our plant we have two Hardinage CNC lathe that machine metals to 0.0001” tolerance the beds are made from epoxy granite. Good material.
Your machine looks like it would be very strong and stiff. I like your explanation on modulus and dampening.
Outstanding information, thank you. I now have the knowledge to make a proper base for my audio turntable (yes, I still play and prefer vinyl records) and my 3D printer.
good luck carrying those lol crtv style
Well done young man!?! The most beautiful and solid machine base I've seen outside of pure granite
Using a better mixture of quartz aggregates from 3/8" to flour allows the resin mix to be only 8%, which reduces cost and greatly improves the mechanical properties
Hello Adam!
Good choice for the base but I was more interested in the precision aluminium sections and how you went about procuring them.
Perhaps you could try the electro magnetic vibrator ( without a motor and eccentric weights ), which have a small amplitude of vibration about 1.6 mm, also used by construction people.
Also you could use silica flour as fines. This and the sand should be dry as the heat generated will release some steam.
Anyway you've been acquiring the skills as you went along.
Best wishes!
You don't need a shaker table, you can get an old SDS hammer drill for very cheap and it will make your hole workshop table shake like crazy
This takes it to that next level. With this technique, it would be interesting if applied to a desktop lathe either hybrid or one off. They do suffer vibrations something fierce. Great build and presentation!
Check AwesomeCNCFreak out, he has made some interesting little CNC machines and one of them uses exactly that :)
Nitpick: your design criteria was all about the material science of epoxy granite but my layman's assessment of your prototyping was what looked/poured best. While air gaps are probably not great, how can you know if some ratio with air bubbles might be much better than what you went with in the end? You didn't test the characteristics you chose it for via any means I saw: vibration resistance and stiffness. Thoughts?
A bit harsh perhaps, but I agree. The design aims are mixed up. If impeccable surface finish is important then use a gel coat or post process in the old fashioned way with filler and sanding. If a very specific mix of rigidity and vibrational damping is top priority, then they are mutually contradictory. A rigid material does not damp; a damping material cannot be rigid. There was no evaluation of the result.
@@raykent3211 Whoops. Didn't mean to be harsh, just objective! There was a lot of background given on the material choice and explaining the challenging blend of properties you mention: rigidity and damping. I guess I interpreted this as a technical focus, so it surprised me that none of the introduction material came back up during evaluation. That's all. Maybe it's sufficient to say "this material was known a priori to be great and thus as long as we use it, all that matters is the practical aspect of forming it well and having it smooth." Like if "wood" had the right property, then perhaps that's sufficient and an evaluation between maple, walnut, or pine don't matter. Dunno, but wondered the author's thoughts.
@@johnhendy1281 it's certainly an intriguing subject and not easy! My only reference is acoustic damping. The key seems to be near-continuous impedance variation. Realistically, the sound hits a low impedance (not stiff) material to avoid reflection and progresses through layers of increasing stiffness ending with maybe concrete. It's a matter of absorbing energy and minimizing reflection and propagation. But the energy can only be absorbed if the source is allowed to move, which for many machines is bad. I doubt if anyone would want a cnc spindle mounted in anything less than a perfectly rigid way.
@@raykent3211 With machines, there is already high impulse vibration in the metal. This is a bit unlike acoustic damping, where you need to pull the vibrations out of the less dense air and have to progressively absorb into more dense materials.
The alu will carry the vibrations (usually unfortunately well). So by casting around the alu, the alu becomes a carrier to transfer to the absorber. This works similarly well with filling box beams. Though their outer surface can still carry some vibrations. If you imagine them trying to resonate, the semi-squish and mass of the super absorber material eats up all the inward pulses. That makes it extremely good at sapping any harmonics from growing.
Maybe I am assuming things incorrectly, but reducing air bubbles/pockets maximizes the density of the base, therefore adding more mass to lessen the vibrations. He most likely could just get away with having some air bubbles but if the final mixture can have better density and requires less variety of materials, it would simply be better to use the chosen material composition. And perhaps (could be really wrong) in extreme cases where excess vibrations are transmitted to the granite base, the pockets could act as stress risers potentially creating failure points, thus propagating cracks.
I just watched a special on submarines and carbon black as a dye adds to sound and vibration deadening by multitudes very interestingly I'll be using it if I try that that's actually why submarines are black even though blue would be better so as no to be seen and a palm sander on its side vibrates the bubbles out just fine vibrating it along the sides of mold
Some suggestions:
1. To improve mechanical characteristics, use
- a single digit percentage of epoxy
- an aggregate with significantly better packing density
- preferably grey cast iron or at least steel as reinforcing and interface members as its CTE matches that of the composite described above
2. Feel free to coat the inside of the mold w/ your material of choice (most of the time I use carbon-filled (i.e. toner powder) epoxy which gives a nice, shiny, smooth, jet black surface) before you start filling the mold w/ your actual mix. This way you don't have to factor in aesthetics even when you're supposed to design your composite to achieve the best mechanical properties.
3. Reinforcement might not even be necessary at all if your machine frame was designed to take advantage of the compressive strength of the composite, which can be brought up to 200+ MPa if you're open to using a more decent mix.
Machine tool manufacturers don't seem to bother reinforcing their frames.
4. Vibration is the way to go. Vacuum pumps don't take epoxy vapor particularly well.
If you arrange internal cooling to the aluminum frame, it is actually better than steel or cast iron, as it conducts heat 3 times faster, thus you are able to maintain a set temperature easily.
Agreed thats how the machine builder kern has machines with about 1 micron positioning tolerance
Hi sniperasys, could you elaborate on the "more decent mix" you mentioned to have a greater comp. strength?
@@JaakkoF Hei Jaakko, voitko suomentaa tämän neljän kohdan ohjeistuksen ensimmäisen kohdan? En ymmärrä kahta ensimmäistä ranskalaista viivaa.
@@uciaok I'd imagine a much bigger gradient of aggregate size? Like a good concrete 🤔
being careful not to mix in air when mixing will help. Mixing larger batches so your paddle mixer can be kept below the surface.
great video, subscribed!
Amazing videos man and thanks a lot for sharing all the hard work you have done to save us all a lot of time and pain! :)
A few of my ideas...
step 1 mix just clear expoy and harder together brush spray into mold... let it tack up the us a heat gun to pop bubbles... on the surface of mold let it set up for several hours..
Step 2 mix epoxy with harder and black pigment or paint... spray over the clear expoy let it tack and use heat gun to pop bubbles repeat a few times on corners or vertical surfaces where you need thicker covage...let it dry or tack almost dry..
Step 3.. mix expoy part a b add optional dye then add sand.... the harder... apply with spreader or bondo spreader to mold 1/4 to 1/2 thick coat as a surface finish to finished faces.. let it dry
Step4 next day mix expoy with sand and some small gravel...fill mold up to 1/ 4 below desired depth...mix new top coat with expoy sand mix and Harder etc... to give smoother finish on under side
This is how I get flawless smooth expoy granite.
Step one and two in one step: Called Gelcoat.
This is a great method, those surface bubbles haunted me, sounds like your technique would eliminate that. Thanks for sharing!
Step 1 cut a hole in a box.
That’s pretty wild!
I’d love to see of the final product in use.
🇦🇺🤜🏼🤛🏼🍀😎☮️☮️☮️
Great video! I'm planning on reinforcing and expanding my small milling machines column and base and make the switch to linear rails on all 3 axis. This information is very helpful.
He did a good job, but is using way too much resin. It will provide poor mechanical properties.CASTINITE
Hey Adam, such a great addition to your page that, like so many other, I have read tens of times, which have spread the knowledge, experience and inspiration for this amazing technique.
Thank you so much for sharing 🙏🙏🙏
Thank you! Hoping others can build on this and take it even further.
@@AdamBender working at being one of them :)
Now do a video about your way covers. They look great!
Outstanding content. In 2 part polymers with fillers, I have always been told you need to mix part a and b together then mix in the filler to prevent differential adsorption of one part in the filler (sand in your case) which would inhibit a full cure. You're method seems nice since you're not rushed by the curing epoxy during mixing. Did you notice any softness in the end product?
That's what I would do too. But I think the filler proportion here might be too high?
A really great job and demo. Thanks.
absolutely fantastic technical video, good job
Might I suggest drying the sand by baking it in a oven for a while in my limited experience with resin and fillers moisture in the filler really messes with strength and leaves tiny bubbles in the material due to a chemical reaction.
I am thinking about using Aluminium oxide, but I am not sure if the epoxy will be able to bond on it, considering a welding require to break the oxide layer prior to have a good bonding.But then since epoxy stick with pretty much anything, I hope it could be an option.
@@richardphatthenguyen195 it will stick no problem. Just dry it out by baking it at 100c for a few hours and mix as soon as it cools.
You can buy plasterers sand, or kiln dried sand. It has already gone through the process of moisture removal, as long as it's stored properly.
@@CozzyKnowsBest Hey thanks,
I was just under impression that aluminium oxide would be best, but figured out it might be a piece of mind to go straight for your reccomended products. Currently I have 30kg of play sand that also lays around in the house for a while. I might give it also a try like Adam did. Though I am looking for Epoxy seller around Montreal, will be the toughest part.
@@richardphatthenguyen195 Montreal is a huge city. It will not be hard to find epoxy locally.
Thanks a lot man, really pleasant to watch; great videos
Excellent presentation, result and video documentation. Thank you.
thanks for watching Craig
Been wanting to build a cnc mill and saw a cement beam on the ground as I was walking today and it lead me here haha
I have been looking for this for a long time now. Thank you 1000 times. I just finished a steel gantry mill and it vibrates worse than a tuning fork and i need a solution. This is it. I'm going to fill it and encase it with epoxy granite.
lets see it run!!
Best Matt
Yup! This would be a great way to do it!
Another option if you have a tube framed design is to fill the tubes with sand! Sand does a great job at killing vibrations too. Just be careful, it'll make things white heavy! Make sure you have enough power to move your gantry around
Very nicely done, thank you for the video
Well researched excellent tutorial. God Bless you.
Saw your article on this. Recognized immediately from the cover. Nice video and nice projects!
Very interesting. Did you check for the flatness how true and absolutely flat is...?
This is awesome.., why didn't I think of that?!?!
Custom Machine Beds, here I come 👍👍👍
My theory: using a vacuum chamber or high pressure to get the bubbles out will propably lead to maybe only epoxy filling the voids. You want the filler material as dense as possible though. Vibrating the material would be the best choice then I think. Your vibrator table seems to not be sufficient enough, maybe try a small electric motor with an offcenter weight on the shaft, and something to control the motor speed maybe. Would also be cheaper.
Only using sand is also not that great, since it still is kinda coarse. There's some basalt based grit that's used for filling the gaps between walkway stones, it has bigger particles (maybe 1/16") down to dust like particles. Should work nicely.
Is there any way we can see your machine running?
Were you still separating the sand in the final version of the mix? I am curious as to what I should use as a sieve.
How you know the properties of the epoxy granite structure for the FEA analysis? I saw that you made a simulation. Thank you! Very good video!!!
Excellent video! Well done! I love the experimentation.
If anyone is looking for large quantities of black iron oxide, Alpha chemicals sells 10lb bags of it for $10
@Triple M well that was kinda random.....
Nice video! Clearly and logically presented. A few questions. Have you thought of introducing aggregate into the mold as you have a base of epoxy and sand mix in it. In other words use the aggregate as a filler. As you have the vibrating table working the aggregate will sink into the mix quite easily. Second thought. As you have shown that you have access to a vacuum pump how about simply making a vacuum bag out of window setting tape and heavy polyethylene house vapour barrier? Connecting supplies in the form of bag to hose are available in a few places. The pump will only draw the air out of your bag. Your test sample that foamed up most likely never had an actual vacuum drawn but was in a leaking chamber. When I'm doing vacuum veneering I generally use a shop vac to evacuate the bulk of the air and even a small shop vac can create a quite useful vacuum. Useful enough that pretty much anybody that can fold up a heavy plastic bag can get this accomplished. In a pinch good quality duct tape can be used to create and seal up a polyethylene bag.
Filling the mold first will not work as the epoxy will not properly coat the aggregate. With a proper filler mix, which would include larger aggregate, the air cannot be drawn out using a vacuum.
Are plans for the rest of the CNC machine available? Also, I wonder if you could further reduce vibration by filling the hollow aluminum tubes with additional vibration dampening material.
Just curios, why not use steel or aluminum as the mold and final base with the epoxy granite on the inside? Would this not provide the stiffness of steel and the epoxy granite vibration absorption? I am not a engineer, just curious if there would be any reasons why this would not be a good approach.
of course you can do that it just wouldn't look as stylish.
is there any reason to not have the epoxy granite as a show piece while providing vibration dampening?
hello.congralations What kind of a sand was it.and what happens if i use cement with iron rods instead of epoxy ?
I'll take note of your advice, thank you.
After days of research on epoxy floors, I ended up trying the most convenient supply epoxy for samples: my employer's deadstock of ENECON DURAFILL. It filled and leveled my old wood floor perfectly, with no bubbles or nonsense. Too bad it costs $300/gal, but all it takes is one failed pour to lose more, and it really is hard like glass, chem and UV resistant.
Awsome video, very well done and explained
Really enjoyed the video, great and thorough walkthrough!
You, sir, are an artist
Excellent work young man. I am impressed. If you are a college educated Engineer, then I am really impressed as most of them, I have worked with, couldn't find their rear end with a map and both hands.
Hahaha, I am a college educated engineer, but I have spent many long days in shops building things
You can vac the epoxy after mixing but before you pour.
Hi, what if I replace the epoxy with resin? Since resin is way more cheaper than epoxy.
Splendid video, great work!
I have done this with my own recipes and here are some tips and tricks.
1) Pre-heat the sand and resin which helps to speed up curing and removing bubbles as it lowers the viscosity of the resin. ( I didn't get any bubbles without using a vacuum chamber)
2) I mix sand, pea gravel, and crushed rock for mine as it uses less resin (Approx 5-10% resin to other ingredients)
3) Fiberglass resin also works extremely well and this is what I use (40$ at Walmart for a gallon).
4) If you want it to look professional, mix in charcoal powder to give it an extremely black coloring and nice surface finish. I made my powder from aquarium charcoal in a blender.
For my next tests, I will be mixing glass fiber along with the other ingredients to try and increase the composite strength.
I was blown away by this polymer concrete's performance and will not be going back to regular concrete.
finally, good content
What should be the thickness of the sand
Hello, its really good effort, thank you for sharing, do you publish video on milling ?
Do you add some carbone and plastic to the x and z frame too? I guess granite is too heavy and would defeat the purpus of stabelizing the structure?
What?
1. It's not real granite
2. (real) granite is the way to go for stability and precision
Awesome project! Would it not be better to make the exoskeleton out of cast iron?🤔
what about mixing glassfibre within?
This is awesome!
btw is it possible to machine a granite epoxy structure after it has cured and without it cracking?
I was able to drill the material pretty easily (for internal wiring) with a concrete bit, but I never tried machining it. I would imagine the sand would destroy the end mill pretty quickly, but it might work for a bit?
Better to embed aluminum or steel in the material where you want to machine, and machine the metal after it cures.
Great video. Just one small point. It may seem obvious, but you should have emphasised that the mould should be levelled very carfully before pouring the mix.
brilliant video!
Friend i have some problem can i ask for making this base plz😔
extremely good video!!
Incredible work, thank you for sharing - liked and subscribed
Is there a mixing technique which will introduce less air?
Great video. Thanks for sharing the lessons learned!
Thanks for watching! Was definitely a lot of fun building and trialing all of this out
Can you drill, tap, mill, surface grind, scrape that stuff?
You can only drill it. Maybe surface grinding works to, but I've never seen that. Thats why you put aluminum or usually steel plates on the functional surfaces like shown in the video. Some people mold some long nuts into the casting, to get deep threads.
You can definitely drill it with a drill bit meant for concrete. I have done so a few times to pull wires internally through the frame. It drilled without any issue. I did not try milling or grinding it.
Using Alexander Slocum's or Culpepper is a great reference for damping in equipment design.
Super cool any guidance on how to attach a 18 x 6 desk milling machine to a granite surface plate ?
So when it comes to vibration dampening, did anyone ever compare this to the stuff typically used for setting machinery? Stuff like precision grout, or some of the metal based aggregate grouts, or something totally epoxy based like Loctite nordbak?
I would be curious how an epoxy and precision grout would behave. Interesting, would be cool to see some data on vibration dampening effect.
I had never before heard of epoxy granite before today
I started the first polymer concrete casting company in the US in 1988 and have been producing castings for grinding machines, inspection equipment, chip bonders, chemical pump bases, etc, since. CASTINTE
I wonder how that compare tu much less expensive concreat ?
Nice work! I was thinking cast the base from Portland cement mortar, then paint it with dyed epoxy resin, or another type of resin. It would be cheaper and do the same thing. I don't know if you could make it look as good.
For epoxy selection maybe try using a deep pour epoxy? Not sure how it would effect your tests, but it has a far longer cure time that what you were using. 3 days to cure. There are some epoxy out there that cure even slower
nice tutorial, i will see if i build my cnc with epoxy instead of aluminium
I want to make a slightly larger gantry mill but I'm curious instead of using aluminum stock bolted together can you cast the aluminum I would imagine the joints would be much stronger but does the aluminum have to go through some sort of hardening process to make the material stronger? this could be a much cheaper and potentially stronger option if done correctly but gaps in my knowledge is setting me back lol 😹
If you had a machine built out of aluminum extrusion that did not need stiffening, would closed cell foam be better for dampening vibration?
No
Why did you stop doing this machine? I cannot find you on the internet anymore.
I moved onto other projects and things in life. But I thought I'd share the process I learned so others can build on top of it, and keep making it better.
Thanks for watching
is that good idea to use wood as epoxy granite mold?
Why not add some chop strand fiberglass in there? that would really increase the strength
you can also add carbon flakes (carbon fibers) to reinforce
Outstanding. Cheaper than the Dan Gelbart lathe made of 100% granite and probably higher performance.
That lathe build was next level. Benefit to his design is micron level flatness on all axes. It is a true masterpiece.
Thanks for watching!
Definitely not higher performance than his lathe.
What about heat issues related to epoxy?