I’ve been printing with filament for a few years now so I decided to try resin printing. It’s quite different and I don’t recommend it for anyone who doesn’t have a dedicated space. And I mean DEDICATED. The space can not be attached to the rest of their house. The space must be equipped with extremely powerful air filtration systems that can capture ALL the fumes. And you can not allow any of the resin to contaminate other things in your house.
Resin is supposedly safe once cured, so the fact you are working with a liquid is a manageable problem that can be overcome, but the problem is that the fumes of almost all of the commercially viable resins are massively TOXIC. Very toxic. I mean scarring your lungs and making you dizzy and faint kind of toxic.
From what I can tell the chemicals are basically light sensitive epoxy resins with turpentine like thinners in them. In other words the resins will destroy your entire respiratory system and are toxic to breathe and are toxic to touch and are toxic to clean up and anything they touch becomes toxic including the rags you use to clean things up with. The cleaning issue can be overcome, but the fumes?
I tried four different brands before I found something I could use. This process was expensive and very painful but necessary as part of my research and development. I want minis after all. And my business will expand in that direction so I need to spend money to make it.
So where did I begin? Well I bought a Elegoo Mars 2 Pro hoping the seal and filter it has would help. It didn’t. But read on:
I read that water washable resins are much easier to clean up and have less odor so first I tried Creality Water Washable Rapid Resin in Grey. https://www.amazon.com/dp/B08VRP8ZNL It came in a metal container the color was great and it did work. The print stuck to the build plate very easily and the detail was very good. However immediately I knew the resin was going to be a major problem when I opened it.
The volatile chemicals in it damaged my lungs and throat. And this was while operating the printer in a dedicated space that doesn’t share the vent system of the house and in which a door and window was open blocked only by security fencing and in which a powerful blower fan was expelling the air and I only ran it for two hours before I had to shut it off and clean everything. It was horrible!
And this was in the Elegoo Mars 2 Pro resin printer which has a seal around the uv blocking lid and which has a charcoal air filter in it (I’ll write an article article about that at a later date since how they designed that system is highly problematic).
The stuff was so bad that in just a couple of hours of running time and almost no exposure I am still dealing with the effects of the resin coughing up yellow phlegm and having difficulty breathing a week later. This stuff is horrific. But it is water washable. That part is true. But it is entirely unusable and dangerous.
Next I tried a resin specifically advertised as super low odor. It was the Eryone Standard Rapid Resin Super Low Odor in red orange. https://www.amazon.com/dp/B08GYXT31P
The color on the picture says Beige, but the bottle said Red Orange when I got it, but either way I really liked the color. Good for flesh.
It was easy to see the details and the prints were very good. All the problems I had with the print were do to my side of things, however AGAIN the odor was terrible and smelled exactly the same but less powerful. So less odor, not odorless. Completely unusable.
The same chemicals were present, but now the resin wasn’t water washable so cleanup was much harder, but honestly the parts cured in less time outside than the other did and had far less odor when finished curing. It took a week for the other’s odor to fade, but this one a couple of day.
So I will say it was less odor than the Creality stuff; probably about half of the foul potency, but still absolutely wretched and the same burning in my lungs. It just took twice as long to get to the same level of pain.
So once again it only took a while running the machine even with major ventilation even while being in a completely separate part of the house not attached by venting for the volatile chemicals to damage my respiratory system and I found out I couldn’t use it. The color was great. The resin is dangerous poison.
Then I read resins made from soy, so-called Eco Resins are low odor so I tried AnyCubic ECO UV Resin with Low Odor in Macaroon blue. https://www.amazon.com/dp/B07X2VTCVV The color wasn’t great, but was okay and I only got that color because I could get next day delivery.
The smell was different and less potent than any of them I had tried so far. It still bothered me a lot and was impossible to use but I got one successful print out of it before realizing I could use that either. It was the lowest odor I had tried so far but was still burning my lungs and so was also eliminated also. The volatile chemicals are still there. Epoxy smell still present. I was thinking maybe all resins were like this. Just that you pay more for better ones, but that they all were deadly and so unusable. I was starting to feel like I had been tricked and that’s exactly what these resin printer and resin manufacturers ARE DOING TO PEOPLE. They are tricking them into thinking if you take proper precautions you can use this stuff. YOU CAN NOT.
Dare I try again? I had spent around $100 dollars already on resins that I couldn’t use if I counted my shipping in with the cost.
When doing more research I happed upon Matter Hacker’s MH Build resin which again claimed to be low odor. I was lery of course. I didn’t want to be tricked again. But what was different that caught my eye is that it said it contained no epoxy. https://www.matterhackers.com/store/c/mh-build-series-resin
Now I don’t know much about the chemicals in uv resin, but the others did smell like a super strong epoxy so I thought it might be worth a chance to try something that said it had no epoxy especially since my 3d printer cost me $300 and almost another $100 in resin and I still couldn’t use it. So I was willing to try at least one more resin.
I’m so glad I did.
What is weird about this stuff though is it comes in bags and you have to buy an empty bottle for any excess you have to save after emptying the vat. They do that to save production cost which makes the resin cheaper when ordering subsequently to the first purchase. That was fine as the total cost of the order for one pouch of clear resin, a bottle, and shipping was less than $40 which is what I figured a good resin would cost me.
The shipping was very low cost and it arrived in two days! Very fast shipping. I was impressed already. I was worried the bag would be pierced, but it came in a box that was strong so that was good, though knowing how delivery companies are they should probably ship it welded inside an expunged propane tank. The Creality poison came in a stainless steel bottle, which is a lot safer, and the other brands in plastic bottles like you can buy empty off the Matter Hackers website, but like I wrote the company is keeping the cost down and this stuff is supposedly less toxic, so whatever. They could improve their safety a bit there, but the box was sufficient and everything arrived in perfect condition including the box. :)
I braced myself and dared to smell it. And I must say the resin has virtually no odor at all. It doesn’t burn my lungs. I had cleaned my machine extremely well days before because I had to get rid of the old poison, but still some odor remained internally and I could tell, but I could also tell the new stuff had no real odor except an oily smell.
It does make the air a little heavy requiring massive ventilation still to be safe and to facilitate easy breathing and I still would NEVER allow the printer to run in my house, however my printer is actually usable now because of this miracle resin.
It smells like a linseed or safflower oil but maybe a little stronger than those, but with less of a nutty smell than linseed. Basically odorless, but you can tell you’ve sniffed an oil because it’s a little heavy.
The comparison to painting oils might be appropriate. You see I ordered the clear because I read clear resins have less odor and I do like printing clear. It’s just a bit yellow at first but clarifies when curing in the sun like linseed oil does. And it’s thick like linseed oil unlike the other resins which were very thin. The odor of the others was probably partly due to a thinner.
So having no real idea I suspect the Matter Hackers MH Build resin might be based on safflower or linseed oil since the smell and properties are similar. It’s a working theory and a comparison that helps me understand how to work with it anyway and that’ll help me out going forward.
You see safflower oil is very clear and is used to make white oil paint because it yellows less, so it’s quite possible some natural polymerizing oil is being used and that process or polymerization and curing is just being sped up with the photo-sensitizing chemical. Perhaps that’s all 3d printed resin is or maybe something quite similar, but maybe some of the companies thin it down with mineral spirits. However I know I’ve read that 3d printer resin contains styrene and that a lot of the smell comes from that. So maybe the Matter Hacker’s stuff doesn’t? Or maybe it doesn’t have any thinner in it? It’s pretty thick, much more than the other brands. So who knows? You see I noticed the difference between brands of resin just like I noticed the difference between odorless mineral spirits used in painting and the smell was quite similar.
Daley Rowney odorless mineral spirits for painting smells really bad whereas Gamsol is more refined and smells better. They refine the product to slow the evaporation rate. I can’t really use either when painting because both bother me a lot, but Gamsol is significantly better and Daler Rowney smells a lot like the enamel thinner than modelers use made by Testors.
So maybe similar chemistry is being used in the printer resins as is used in oil paint, just with the photo-sensitizing agent as an additive to accelerate the curing process. After all there are water soluble oil paints now just like how there are water soluble uv resins now and there are soy based oil paints just like how there are soy based eco-resins.
So maybe some styrene is still present, but maybe more oil is being used it the matter hackers stuff to create more of the bulk of the model. That would explain why Matter Hackers was able to make the stuff smell so much better, but why it is thicker and why it has some trouble adhering to the build plate. But these are just guesses, but as I said it provides a working theory to help me use it and to make it work for me and perhaps how to modify it if I ever need to.
Either way I am pleased with the product and have used it for three figures. The figures look good and have the level of detail I need and so it works for me. The strength is what I need for a miniature being just a bit flexible, but more or less ridged. It’s good stuff. It’s kind of thick and sticky so needs to be cleaned more thoroughly from the part and build plate, but pours off the vat easily enough (though to be fair I grease my vat). It’s not too hard to clean up with 91% isopropyl alcohol but the part should be cleaned before supports are removed and immediately after and rubbed with a soft toothbrush to get it really clean and then air dried and then cleaned in fresh alcohol again. I also have Mean Green Super Strength Cleanser and Degreaser to clean the machine with and the parts, but I haven’t used it on models yet, so I’ll let you know how that works out, but it cleans the build plate really well but I finish with alcohol. Mean Green is a light green and I was using clear resin so I didn’t want to make the model green and thought it might so I used only alcohol on the model.
Now I have no idea about the toxicity of the Matter Hackers HM Build resin. I still wear the nitrile gloves, a mask, as they say you must, and I have massive ventilation and will be building an even more powerful filtration system to use while resin printing, but I must say I am thankful to God for this stuff as nothing else worked.
I also like the bags surprisingly. The spout is small and the bags are easy to pour from as long as you are smart enough to grab them by the edges instead of the center you can control how much you put into the vat very easily. A little funnel could facilitate replacing the stuff into the bag directly but that’s too much in my hands and so could cause an accidental spill so I’d rather pour it back into a bottle. Mixing colors in the same bottle wouldn’t hurt anything and would make a grey colour eventually anyway so one bottle is all that is necessary, but if I buy more I’ll probably get a different bottle for each colour.
However there IS a problem with the Matter Hackers MH Build resin. A major problem. The problem is the stuff doesn’t stick to the build plate hardly at all. A lot of failed prints is this stuff’s fatal flaw and the company knows it sending you tips to try to make it work for you and selling a build plate that is supposedly helpful, but people haven’t had much success with that either from what I’ve read, but I’ll try some as soon as I can get some more money together. It’s sticky backed stuff that you heavily sand and then apply to the build plate. I suspect people aren’t scoring it enough. It probably needs an aggressive scratching. But we’ll see.
The resin is fairly new so I figure they may modify it in the future if they can figure out a change that can make it stick without adding odor. But for now we have to find mechanical solutions.
For starters the company recommends increasing your lower layer exposure settings as that will help, but only so much, and you can burn out your screen and uv light if you overdo that so that’s no solution and honestly the stuff works fine at normal settings, it just doesn’t stick, but it does cure at 2 seconds per normal layer and 40 seconds bottom layer on my machine because my machine is new and has a monochromatic screen so it’s pretty bright I guess, but maybe bumping that up a little would help. The model was a little sticky after so some tweeking of exposure times might help.
I suspect the sticking problem though is because the stuff is really thick and heavy and viscous. I think the weight of the part and the viscosity is creating suction on the part. I won’t explain how exactly I overcame this, but using a secret method I developed I DID overcome this.
What I can say is that a very roughly sanded or deeply milled build plate would help a lot which is part of what the company recommends. The Elegoo Mars 2 Pro has a sand blasted type finish and even it has a lot of trouble with this stuff. Lightweight models and part seem to do okay, but medium sized models and parts no way. They end up in the vat immediately.
So keeping your parts lightweight will help and having a large surface area for the lower layers will also help and making a model of a thin sheet which you can place on the lowest layers against the build plate will help too. That’s a trick that VOG (Vegetable Oil Guy) deserves credit for (https://www.youtube.com/c/VegOilGuy/videos). But still there is more that can be done and it will work flawlessly, but I can say nothing. God gives some people brains as a gift and others have less intelligence and sharing that gift with others without getting something in return may be charitable but is done too often in the information age and in my opinion if you come up with something truly innovative and simply give it away you are despising your birthright. The only exception I believe is when information could save lives or souls.
But one thing that will help any resin is extra lubricant on the FEP film and that’s no secret. What I used was a bit innovative, but again it’s not enough of an invention to keep a secret. Most people use 3-in-one FETP oil. That’s probably fine, but it’s very liquid and not non-toxic. I wanted something sticky that would stay where I put it.
Greasing the vat with the ever so-thin coat of Crisco Vegetable Shortening applied with a gloved finger will work.
The Crisco is non-toxic although the resin is NOT and there will almost certainly be some cross contamination so take precautions to separate some of your Crisco in another container and mark it for resin printing only. You only need to separate a spoonful probably for hundreds of prints.
The funny thing is I don’t cook with Crisco anyway because it’s a GMO product, but I do use it in a lot of operations around the shop as it’s a good sticky grease that is non-toxic and easy to clean up. It’s very underutilized as a lubricant in my opinion. It’s not great in high temperatures, but it’s been used by black powder shooters and gunsmiths and machinists since time immemorial. Think of it as a lard substitute. If they made a non GMO version I’d even cook with it. I don’t care that it’s “hydrogenated.” I care about sterilization caused by GMO corn. Anyway…
How I apply Crisco Vegetable Shortening to the Vat/Pan: Yes boys; we’re cooking with Crisco. I clean the vat as normal and then use alcohol to clean it more thoroughly and allow that to dry and then lay the vat on some soft paper on the table to protect the bottom and using fresh clean nitrile gloves touch, just touch, don’t gob, a bit of the crisco, just enough to make the tip of your gloved finger shiny and press the pad of your gloved finger against the inside of the fep film near the center and spread it thinly working outward to all the edged and up the sides of the metal vat greasing the pan but being careful to not get it on the outside or underside of the vat or FEP film. I just use a thin thin thin coat, so thin you can easily see through it and the greasing is done. I then use fresh gloves and place the vat in the machine.
They say that if you use a small amount of water with a small amount of dish washing liquid instead of alcohol to clean your vat your FEP film will remain more well lubricated. That’s probably true. I figure regular bar soap would work even better in that regard as it usually contains some type of conditioner.
Either way you can lubricate the FEP film again if you wash it with alcohol, but I would think that if you used too much crisco or you tried to place more in a vat that wasn’t perfectly clean it wouldn’t stick to the bottom and instead might separate and float around which would make it harder, not easier, to get a part to stick to the build plate as the resin would be contaminated with a lubricant.
So greasing the vat will help prevent the part from sticking to the FEP film, but it still may not stick to the build plate even if you are careful to grease the vat properly. But I overcame that problem. How I did it will remain a secret.
I’ll be adding more information about resin printing in the future, but I think it is HIGHLY irresponsible for youtube channels and amazon and the resin printer and resin manufacturers to advertise their products as being low odor when they are so amazingly dangerous.
These resin machines are NOT toys. These are not easy bake ovens or creepy crawler rubber makers for children (both toys my mother said she had that she loved) and they are not gummy candy makers. They are highly specialized machines for 3d modelers to create original models and machine parts and they used POISONOUS resin that creates POISONOUS fumes.
If you get this stuff on you it can form plastic under your skin and cause burns from the volatile chemicals themselves or from exposure to sunlight thereafter. These are super dangerous chemicals and the process of making resin prints much more like developing infrared camera film than anything else I can think of. You have to do it at night if you have windows and you have to have windows to vent the stuff effectively unless you build a special ventilation system with very effective organic volatile chemical filtration which in my opinion is ABSOLUTELY NECESSARY.
Children, animals, and women shouldn’t be anywhere near this stuff and they shouldn’t be near you when you are doing it. Neighbors can be poisoned by it. Even to vent it outside massive ventilation systems with charcoal filters are needed.
And the built in filters that some of the printers have don’t work because they are poorly designed, not sealed at all, and far too small even if they were done correctly. I’ll be explaining how I’ll overcome some of those problems in other articles about improving your printers.
But for now if you have a resin printer I’d suggest switching to the Matter Hackers Build Resin and as a temporary solution heavily and I mean heavily scratch your build plate with tough sand paper meant for cutting steel so as to deeply score it and washing the plate very very well in soapy water with a toothbrush and then with a garden hose on high pressure a few times to remove all the debris before using it again. That’s the only tip I can reveal publicly since it’s fairly obvious, but believe me there are secrets to making the stuff work every time and I am thankful for it. My printer can actually be used now whereas before it could not. Now I want all the colours because I am a pigment piggy.