Easier Fiber-Reinforced Resin Printing! Stronger and Conductive Resin Prints? 

The graphite bubble color is "structural coloration". Unlike a prism, where white light splits due to changing speed between mediums, here the size of the particles is comparable to the wavelength of light and parallel rays will constructively or destructively interfere causing the light to split. It is like a diffraction grating you might have played around with or a grating wavelength selector in spectroscopy.

I love this kind of experimenting! Also you need to try ceramic resin

Great video. Since inconsistent curing from settlements can weaken a print, we recommend using a thicker, tough resin as the base for this type of experiment. This way, the materials do not settle too quickly, and you have a very strong resin to start to stay functional. Happy to get you some Blu or Tenacious to play.

Really liked the cinematics during the break test clips.

Give milled fiberglass a try instead of chopped fiber, it looks similar to the cotton you used, its a common filler with composites.

Me: Maybe try glitter? Katelyn: Hey, Evan - hold my beer...

In most injection molded parts with glass fiber there is at least 30% fill. Most structural composite layups are at least 50% fiber

Hey man, great video! If you want to achieve a truly mechanical reinforment of your SLA resin you have to add functionalized fibers/particles. Functionalization of fibers/particles improves the chemical affinity between the fiber/particle and the polymer matrix. You can purchase functionalized fibers/particles ready to use or you can functionalize them yourself (using a silane coupling agent). Cheers

I've printed cycloidal gears with graphite additives, also adding a small amount of flex filament to 10%. Makes for a very strong part that is partially self lubricating and tough. The flex adds more strain relief albeit at the sacrifice of rigidity- but that slight flex is great to make up for the slop and inaccuracy of the print.

I would be interesting to see the LCD replacement process.

I am excited to see a follow up for the other fiber-reinforced prints

Your cinematic shots have gotten really good. Keep it up!

Hi Thomas, great job. Your videos are inspirational. Btw, I am a materials eng. Scientist. Is a long time that I don't get into the polimers side, but as you analyzed, add fiber or other materials can deteriorate the properties because a lack o bound between the matrix and the aggregate. It not necessary forms micro cracking around but can help the cracking propagate faster on the aggregate material surface because it's is not properly bounded. Most composites have a mix of polimers or other compounds that helps bound the matrix to the aggregate, same principle of soap and water to remove fat. Let me know if you need more information about it.

I very much appreciate tech creators who also show failures, not just success after success. That's the engineering/scientific process. Good engineers/scientists have a high tolerance for failure, building on it rather than giving up. It is often the failures in pursuit of a goal that create spin-offs enabling entirely new directions and new goals. Such as adding carbon for color and perhaps lubrication, rather than for strength.

The best method of reenforcement I've found is likely not what your looking for. But when I need strength, I print with a hole though the part and use an epoxy resin to secure a metal rod inside.

Some one has been watching project farm.

That was a brilliant test montage! 👍 These experiment videos are so good, they explore concepts I never would have otherwise come across, thank you Tom! 💙💜

Man, the editing during the testing was A++!

At 8:30.. maybe lock your vat down?

Tom I've been watching you for years. I very much appreciate that you're on the same track I am, for me a particular print that I am trying to make stronger for someone. Before I saw your video for the last time you added fiberglass I was at the beginning of my adventure and that time the only glass fiber reinforced prints I saw was someone making a shell and then filling with epoxy mixed with glass fibers. I am very appreciative to see that the first test with glass blankets was not that good in strength. Saved me from the mess. I had just boughten chopped glass fibers and received them when I came across your video and was like "damn it someone beat me to it". but I appreciate you going through all the messy stuff and displaying your results saves me a lot of headaches and I just want to say thank you. Also, I never thought of cotton. Brilliant! Also the graphite I want to try now. thank you for the wealth of knowledge you have shared over many years.

I really enjoyed watching the video. I can imagine how messy those tests must have been. As this video was recorded two years ago, it would be great to see how the new generation of resins would perform. Without mixing anything additives into them, but mixing resins with each other.

One thing to note: Short fibers are useless for strength or structure. However, I believe by adding the short fibers to your resin, it may have a larger impact on ABRASION resistance, than adding strength. Being in custom/restoration/collision for 30 years, when I have to fix an older Corvette door I use the long strand glass mat for structure then a shorter fiber/filler mix to cover any hard edges before applying a finish putty before primer and paint. USC Duraglass, and a product called Fiber-all are basically body fillers with short strand glass fibers pre mixed in. I use them sometimes where chipping might be a problem, like a corner or edge of a door for example, where the panel doesn't line up perfectly to the next panel. Hope this helps. Been subscribed since I bought my Wanhao i3 v1.2 back in 2015 (currently rocking an SKR 1.4 and 2209's), and since have upgraded the poop out of it thanks to more than a few of your videos and tutorials. I have a Mars 2 Pro also and found this video very interesting and educational. Cheers from the USA!

„We're gonna test that!“ Getting strong Project Farm vibes here! 😄

I absolutely love graphite powder, I combine with epoxy resins all the time when casting

I like the music montage of the stress testing. I never cared to watch each and every test. One test filmed to show the procedure, yes, but then cut to the results. Your presentation was very enjoyable to watch. I wish more people would film this way.

Dude, LOVE the editing in the montage for the testing!

Really love the SLA experimenting!

The graphite results with regard to visual appearance and potential for self-lubrication are definitely interesting. Worth keeping in mind. Loved the music/stress test montage. You are definitely stepping up your video productions.

I appreciate you runing all your equipment and free time to hopefully help me avoid doing so as well

Hours and hours spent to make this. Awesome Science-ing. Mind you it has given me clues for resin printing. I was so keen to cut over to Resin printing for the absolute beauty of the outputs, snag is the parts are not tough enough for me.

Nice methodical approach. I found your videos because I wondered about adding fiber materials to the resin mix to improve strength. I would repeat some of the experiments using "tough resin", which has ground rubber mixed in to reduce the brittleness. Use a squeeze bottle to blow a little milled carbon in the first 5 and last 5 layers. Blowing will confine the carbon to the outside layers while keeping the inner layers almost pure resin. It will create a stronger skin on the outside.

Thank you Thomas, very informative and enlightening.

Very cool experiments, thanks for showing your results! My one contribution as someone with a materials science/mechanical engineering background is to remember that there are still more mechanical properties than strength. A lot of times composites represent a tradeoff between stiffness and strength, where you increase the stiffness over the base resin/matrix, but make it more brittle. This would reduce the energy absorbed during impact. With the short fiber systems, though, you tend not to see much increase in strength, particularly at low volume fractions, because you don't have enough load "continuity" for lack of a better word. In long/continuous fiber systems, for example, even when the matrix fails, the fibers can still bear load. Here, there's enough space between fibers that failures can just propagate through. I'd also agree with other comments that improper bonding/wetting between fiber and resin could contribute. Could be interesting to look at in future tests. Doesn't require an electron microscope, just a decent power optical. You can even experiment with the $20 or so digital microscopes to see what kind of images you can get.

Ive been adding stuff to my resin for months.. but you got to remember the way the layers work to get some nice effects for knife handles and models.

I plan on making bushings and gears with graphite. Guides as well. Great video.

I liked this video - seems different than most recent videos to come out recently - was getting tired of everyones printer reviews, thanks mate :)

Great Video Thomas...you ask about the reason why the filled parts are loosing strength...most fillers in a resin binder system need an additive that allows the resin to bond to the surface of the filler. Otherwise, as you have shown...the properties will suffer. One of the more common families of bonding or coupling agents is silanes from Dow Chemical...depending on the resin, the particular coupling agent is chosen for a particular filler...I formulated 2 part spray-able polyurethanes and polyureas that after leaving the spray gun would be dry to the touch in just seconds. Your other problem is likely you need a Much Higher shearing action of the reinforcing materials far beyond what a magnetic stirrer can provide...they are fine for liquid to liquid mixing, but Do Not really totally wet out the surfaces of the filler to liquid interface. Thus, first you need to find the proper coupling agent for the fiber and polymer, second use a High Speed Disperser, and finally vacuum out all of the air bubbles. Keep up the Great Work!!!

Love the test compilation!!

Has anyone tried to make resin and graphite bearings or bushings?

interesting experimentations ...great video 👏

8:30 The vat is moving up and down with the moving platform?! (See corner on the right) Did you forget to tighten the two screws?

Great Video Thomas! I never tried a resin printer, but I have some experience with glass and carbon fibers. I think some other fillers could also be interesting. There are for example glas micro balloons with 0,12 g/cm^2 and a particle size of just 65nm to make very light weight components. To reinforce the resin a good try could be to mix milled glas fibre (0,2 mm) and finer cotton flocks (0,35 mm fibre length). Some fumed silica like Aerosil could also help to thicken the resin, that the chopped fibers don't saddle down to the bottom. It looks a bit like, that the chopped fibers in your prints are not completely wetten, normally they should get very transparent in the resin.

Good to see that 5% of Colton made it into a print. :P

Dorsnt the fiber impede the curing light from shining through? Especially the carbon I would think would absorb the UV

I work for a National Laboratory and 3 years ago we tried Graphite and/or Iron filings in the resin of a Laser SLA printer to try and see what concentration (if at all) it would take to get conductive/magnetic properties out of a 3d printed part and determined really quickly that at higher concentrations the slurry becomes to tick to work with the printer and at the maximum saturation point that does allow the prints to work the resin acts like an insulator at a microscopic level and simply will not allow a continuous current to run through it.

"We're gonna test that" My favorite to hear.

The testing montage is really cool!)

Interesting idea for Thomas: Make replaceable Gibs for a dovetail mill out of graphite infused resin. As the resin is worn away the nodules of graphite can act as dry lube for the mill ways

loved the testing montage

Light is reflected from the outer surface and the inner surface of the bubbles, As the thickness is very thin,there is a difference in the refraction angle and it forms a miniature prism effect. Love the experiment.

I'm close to buying a resin printer and is still learning about them before my purchase. My main hobby is RC cars/trucks, where we use dry wall to reinforce the body shells, and of course most knows that the higher quality cars always have a composite plastic used. Maybe this would be your source of information? I have for some time tested parts for a manufacturer and the character of the parts significantly changed depending on direction/amount of fibers used. But the key secret is that the fibers are overlapping so the force can't slip through, but still in a small amount that the parts still have flexibility. Great videos as always Thanks you

Love it! Please do more resin review videos, we would love to know which resins to buy as there are many confusing products out there.

Very interesting. Thank you. Do you have the reference of your vacuum chamber and pump?

You can get kevlar that is similarly fine to that cotton. May be worth a try...

So, I just watched Tech Ingredients' video on making graphene, and he showed an impressive increase in the bending resistance strength by putting a tiny amount of graphene in some epoxy resin. Of course, one of my first thoughts is if this could be used in UV resin. Would love to see you do a video on this!

Lovely video

I really wanna try to make a continuous fiber laying tool for my doot changer but i'm tired and lazy and doubtful i could get it working, specially with my tools and skill! BUT THIS IS WHy i love this channel so much :D awesome video!

Great edditing and nice songs, thanks for the great entertainment

I once made epoxy resin reinforce with carbon nano tubes, in several concentrations, it did not improve the tensile strength but they where more conductive.

Not a materials engineer either, here; but, you can think of what you're doing as creating inclusions in the resin. Inclusions in metal causes the metal to fracture over time in certain conditions. If the particles you are mixing in are larger than the particulate size of the material making up the resin, you may or may not get a good bond. Remember, in fiberglass for example you are working with a woven cloth base that already has strength in and of itself. By incorporating simple fibers, you don't have the strength you tend to get from weave. And if you aren't careful with the resin application, it won't soak through the weave - leaving voids and leading to delamination. Love seeing you do these tests tho. This is the core of the hacker experience - test, experiment, learn. And good to see Siraya Tech chiming in. Though it does make me wonder if approaching this with a fine weave material at each layer or every so many layers would make a difference. Food for thought. Something like silk...

The glass fibers are clumped together because they're coated in something called a sizing agent. Sizing agents are essentially coatings that cover the fibers. Because glass fibers are chemically inert they will not bond with any kind of resin or epoxy matrix. These sizing agents have two fold benefits, they allow for this chemical bridge (aka a coupling agent, for glass fibers it's typically a silane) to bond to matrices and add a protective layer to the outside of the fibers for easier handling. They also bond the fibers together, that's why its so hard to pull the individual fibers apart, they're essentially glued together. That being said you can just sonicate the fibers to loosen and separate them.

The reason for the "holographic" effect you saw in the graphite resin is that the flakes of graphite are orienting themselves with the flow of the liquid, so that their reflective surfaces are tangent to its flow - creating what is known as a "rheoscopic" or current-showing effect. In the bubbles, I'm pretty sure what's happening is the super-fine particles of graphite are causing an effect called thin-film interference, where the reflected light from the top and bottom surface of the material are different wavelengths and start to interfere with one another, causing those wild colors to emerge. The same effect is visible in soap bubbles to a milder degree

Interesting, great testing montage btw.

If you want to improve the mechanical properties of your resin parts, you can do two things. 1.) Print at an elevated temperature of 25°C-35°c 2.) Cure under water (prevents oxygen to inhibit the curing process) + cure under hot water (heat equals vibration, vibration helps in the bonding process between the molecules during curing). Both of those measures should help significantly (About +50% more strength) Adding anything to the mix weakens your parts since those molecules can not bind properly anymore and have to bridge a gap because of the "impurities" you have now introduced. Fiber reinforcement works well with epoxy resins because those don´t need UV light to cure, properly mixed they will always bond to anything.

Nice Video. I am trying to SLA print with anti static property. So, I was wondering if adding a little bit of graphite will make the parts anti static? Please let me know. Thsnks

you can level the bed in the vat? I was using the paper like the instructions say.

Would you be willing to test out the graphite with ceramic resin? Like the one Integza uses

The problem is that in a composite material, the purpose of the resin matrix is to transfer load from one fiber to the next. If you don't add enough fiber, you're just introducing impurities and therefore reducing strength. And you can't add enough fiber and still have a successful print with the way that lcd/sla printers operate.

It's only a theory, butI believe the fibers will impede the ability of the resin to fully cure by occluding the light paths to all areas of the resin. The masked resin is left to cure partially with refracted light from the subsequent layers. I'm not a composite expert, but I've been around materials a lot, and have some related experience.

Yep, confirm what many people say here. Milled fibers or glass spheres are usually used as reinforcement. Large chunks of GF in small quantities are just useless. Hoping to see the update to this experiment. Also, GF should be mixed by volume, not weight. Try 30 to 50%

What about powder pigments? if you are gonna use graphite only for the colour maybe you can add pigments like in Epoxy without a significan drop in strength

the colors on graphite bubbles are caused by an effect called *thin film interference* , where basically light passing through the upper and lower part of the bubbles interfere with one another enhancing the reflected light.

@8:30 why is the vat moving vertically with the retraction?

Could you test the self lubrication of the graphite in the printed part?

Nice one just wondering which resin would you recommend for rc parts similar to rpm that will have flex and don’t snap thank you in advance

What might be good to try for artistic looks is mica powders. They are used in resin projects but haven't seen in SLA.

I like the visual effect of the graphite. I wonder what it would look like if you were to use some of the pigments that they use in poured resin tables, coasters etc.

I use Mica powder for painting and resin craft.. can i mix mica powder in resin to print?

What about small glass spheres? Or what about glass fibers, but in a powder like form?

I think a lot of the problem with this is that, while the particles (cotton and chopped fibre especially) are adding strength to each layer, they are only adding strength within that layer. Because of the way SLA builds the object, you're not getting any cross-links between layers, so it is exactly as strong as a normal object in unenhanced resin.

Hi Thomas I wonder is it possible to print two materials of the same base matrix but may be different colors? If possible, can you show us how?

I think a great idea to test is trying to print on higher temperatures. Heat the vat and print and see how it affects the part. Bc polymer chains would usually be longer under higher temperature, and the material might be slightly better in terms of strenght, heat resistance etc.

Did you test conductivity of the graphite prints? I would be curious if they were able to be metal plated with that low percentage of graphite.

is it helpful to put resin in vacuum chamber ? will it make my part more accurate or stronger ?

Any chance you could do some tests on the resin fumes? I just bought a resin printer, but i live in a one room apartment, so I'm curious as to how safe it would be to have the printer in the same room I'm in.

Do you think graphite ones can be as much conductive To work by electroplating.thanks

You should try cotton and fiberglas at the same time. The cotton makes the resin thicker, so the fiberglas can stay chaotic in the resin and doesnt sink to the bottom and stay flat. But maybe the printsurface squeeze everythink down and flatten it. Thats why a bigger resin container could be needed. So the fiberglas mixture can easier flow to the side and back after the printsurface goes down and up.

Hi, what solvent do you use to clean the resin prints? Looks like sth. meant for the grill :) I'm looking for a cheaper alternative that works as well as IPA.

i wanna try this but by seperating the chopped fiber, not the length but width. pull part the strands

Nice video, suprising results! Maybe cleanroom wipes as material? Either chopped up or in layers. Those are a bit like paper towels, but specifically designed to not shed particles and are extremely strong in one direction. So if you criss-cross the layers it might result in a really strong part.

I was hoping you'd mention the lubricating effects of resin, glad you said something at the end. It makes me think of oil impregnated bushings. In addition to that, I'm very curious about thermal conductivity of those graphite parts. We messed around with some plastics at work filled with something and I want to say it was graphite. Although they lost flexibility, they had a very "cool to the touch" feel and that's exactly what we were going for. Trying to get thermal transfer improvements through the part.

Thin Film Interference is where the color is coming from and the black background gives greater contrast

can u try electroplating the graphite one ? even tho it have high resistance it can be electroplate as long as it's somehow conductive or just try paiting with graphite then electroplating with copper and nickel it will make the part stronger but the real question is how much stronger? i would love to see u making a vid about this

The most popular additive for improving tensile strength is probably Siraya Tech Tenacious resin. Everyone seems to have their own preferred ratio. I'd love to see this kind of rigor put to testing different ratios. Maybe you can get Siraya Tech to sponsor a video.

With the Graphite resin I wonder if you could give it a light sanding and cleaning and electroplate it

At 8:30 my heart just dropped. Made that mistake before. You forgot to tighten the screws for the resin vat

Curious what the FEP looks like after using these materials.

Could it be the effect is similar to some FDM fiber reinforced filaments? Lower tensile strength and impact resistance but higher stiffness?

Not sure if it's been mentioned. I use resin as a filler/primer by mixing it with sodium bicarbonate, about 40/60 and it helps the resin thicker and stays suspend quite well. It could help hold the heavier filler/additives.

When you start your print hook up a pwm as it prints out so that when it prints out with the graphine/graphite, there will be a line for the electricity to follow