Why You Should Be Water Curing Your Resin 3D Prints (Especially Hollow Ones)

[@srboromir452]

I work in Dental, our biocompatible resins are all cured submerged in glycerin. Some really high end setups are cured in inert gas chambers. The main benefit is you don't have a reaction layer on the outside of your print. Resin curing is inhibited by the presence of oxygen, that's why you end up with a tacky layer on the outside of prints even after curing, cured in an oxygen free environment, especially at high heat (our glycerin is heated to 150- 160°F) gives a more complete polymerization. Curing in water/glycerin also controls temperature, i find my models warp less when cured submerged

[@TheSmuey]

FINALLY! I've been recommending EXACTLY this for the past two years and every time I brought it up, people just didn't believe it actually works... Which is weird, because trying it is literally as simple as just dunking a model in some water before hitting it with UV. There was, at one point, even a resin manufacturer that recommended curing models printed in their resin under water as the optimal way to approach it.

[@GrayScalpMiniatures]

Nice to hear others are using it as well with good results. Interesting reading through the comments and seeing that some people use similar in really high end setups.

[@grazingshot]

There is a bit of misunderstanding I want to try to help clear up. Resin absolutely does not build up gases over time. This is misunderstanding in the community posted by one person that got it very wrong, and it has continued to spread as it seems almost reasonable. This is very easy for you to test for yourself. Take a print, and without curing it put it in a zip lock bag. Check back on it after 1 week, 1 month and longer. You will find no additional air in the bag. Note that no resin manufacturer talks about off gassing as it's not an actual process that needs to be worried about. The real reason that resin prints crack is due to poor cleaning, specifically that the inside of the hollow print my be cleaned and let fully dry so there is no liquid left inside. The process that leads to cracking prints is due to the fact that resin absorbs liquid. Some resins do this faster then others(this is what leads water washable to crack sooner then regular resin). When resin absorbs liquid it will do 2 things, first is that it will become softer. Second is that it will swell. This is why cracked prints appear to be curling out from the inside and will be oozing liquid. With this in mind, curing the inside of the prints isn't actually required. Proper cleaning is. Have at least 2 holes in the print so that the cleaner can enter the inside, fill and empty the cavity several times, then leave the print to fully dry without covering the holes.

[@GrayScalpMiniatures]

Thanks for that explanation! That’s really interesting to read and definitely helpful going forward.

[@alertedcoyote7892]

Thats really interesting, so for say a Water Washable resin, if its properly cleaned and dried it won't crack, is that correct? Assuming you then keep them in a relatively dry place and all the usual stuff. Also, does that mean it's better to print models without hollowing them, as there's no internal space to have liquid caught in?

[@NobodyInTraining]

Thank you for all your comments in this thread

[@johnharreld4875]

That's much more believable, thanks!

[@yayi360]

Printing my hollowed models in clear resin makes my curing so easy

[@AbdulAziz-cj4hg]

Yeah me too😅

[@_Mach3]

Genius.

[@hyosworld109]

I recently started using this on my minis. It's sooo fast and even! Good to know it works as well on larger parts

[@GrayScalpMiniatures]

It’s larger prints that sent me on this experiment and it works great!

[@mistakitty]

I've been doing this for years as well, other than the oxygen one other thing it comes down to water not absorbing UV light (technically just the specific wavelengths for curing) like it does with regular light. I put my water container in a round bin that has aluminum foil spray glued inside for a smooth reflective finish, making a nice UV oven -I figured cylinders are better for reflection but never really did tests. Another nice tip is to heat your resin with a heat gun for a few seconds to get any air bubbles out right before you hit print.

[@samanthalacroix2687]

Glad I saw this as I will be making some very big models soon, including that big bug you showed and I would have had NO idea about gas build up.

[@GrayScalpMiniatures]

Glad I could help. I lost a few big prints to this early on where I hadn't properly cleaned and cured the inside, and so far this has been working to prevent that. Good luck with the big bug!

[@sriramseshagiri170]

I am so happy I stumbled upon your video! This works like magic!!

[@juandiegovelez6283]

Hi dentists here, we do glicerin for curing 3d prints, also the effect of the glicerin/water on the surface avoid the formation of a layer that forms with superficial oxigen called inhibited layer, it also happens on teeth composites, the curing material basics are sort of the same

[@ItsDrMcQuack]

I wonder how it would affect curing if you added a small amount of white dye to the water to make the light diffuse even more. Like when you shine a light at a water bottle to create a camping lamp: add a small splash of milk to make the lamp much more effective. Wouldn't use milk with resin figures, but maybe a white ink or paint could do something similar

[@DaggeeggaD]

Great that you are spreading the knowledge about water curing! I've slimlined the process by removing supports in a glas jar witj luke warm water then I use the same water in the glas jar to cure the models in the next step.

[@GrinningJest3r]

Do you have a dedicated pot to put the water back in to heat it for the next print? Or what do you do with the water once you're done?

[@DaggeeggaD]

@@GrinningJest3r I reuse it a few times then pour it in the drain. It's cured anyway regarding any residues.

[@bolee6901]

Does this process help prevent the clear resins from hazing when curing? I have tried clear and it stay clear until I hit it with UV and then it hazes up. Trying to make helicopter canopies and looking for the best way to make it come out clear.

[@TB1439]

I am a bit hesitant about it. I have had "Burst airbubble" holes surface on my resin when doing that. I do not know if it has anything to do with bad pre cleaning.

[@soup_bone]

How long are you curing prints for? 2mins cures fine with no water but stuff was still a bit tacky in the water, it took about 6 mins to cure in the water fully but it also warped my prints.

[@WarhammerWings]

I'll have to try this if I ever get a 3D printer.

[@TableFlipFoundry]

Can you please site the research you did. I'd like to see if the claims about water curing are founded in some science and experimentation and testing. I run a large 3d printing community and I'm always looking to share verified accurate information.

[@Ale-bj7nd]

What do you think abou lt using water washable resins and doing clean and start curing after a delay?

[@ntw3002]

What do you do with the water afterwards? Is it ok to pour away?

[@allanlarsen3261]

I haven't tried water curing myself, but I think it is quite safe to just pour the water down the drain after the curing process. For two main reasons. 1. The parts should be thoroughly cleaned before water curing, leaving only very minimal resin to get into the water. 2. Any resin particles which do get into the water, are exposed to the same UV light as the parts, curing them as well. This of course assume that the UV light can hit all the water and not just a part of it. If you use a large water tank and a small UV source, this might not be the case. I would not drink the left over water as it might contain microscopic cured resin parts, but it should be safe to pour down the drain.

[@grazingshot]

@@allanlarsen3261 This is incorrect as well. It should absolutely not be poured down any drain system. After being submerged the resin will be diluted, while the uv activator will all be absorbed not all of the chemicals will be. UV resin is considered very toxic to marine life(it's actually rated toxic for marine life, and it's not actually harmful enough to be rated toxic to humans)

[@KilianOlen]

For anyone that comes here later, know that you should treat it as any other hazardous waste. Even if you can't "see" any resin in it, by exposing uncured resin with water, you've contaminated it. You can either dispose of it at your local hazardous waste center, or you can let the water evaporate.

[@felixxcatus]

I'm trying a new resin and water curing is not working very well, I think it's absorbing some of the water and causing complications down the road (cracking) or maybe that's from something else

[@DanielChaves1984]

how long do you cure for?

[@LaserJake99]

I'm sure O2 inhibition has a lot to do with your tackiness. Try purging your cure box with argon or N2

[@7901Sparrow]

Is this just for resin that requires isopropyl alcohol?

[@GrayScalpMiniatures]

It should also work for water washable resin, but you’d still need to make sure you cleaned the print first and then use fresh water for the curing.

[@AAw3s0m3]

I was just about to ask regarding ww resin. Thanks for that response.@@GrayScalpMiniatures

[@grazingshot]

@@AAw3s0m3 He is mistaken. This should not be done with water washable.

[@secondarycontainment4727]

Why not just UV cure in IPA?

[@srboromir452]

Resin should be in contact with IPA for no longer than 5 minutes, including the cleaning step, it will break down the resin, it's a solvent. In the medical industry we cure our parts in 150°F glycerin.

[@chanyenyee9795]

the dissolved resin will gunk up the print if cured in IPA, plus I heard is better to let the IPA completely evaporate before curing it

[@paintrosered]

Does this method work with a water-washable resin?

[@grazingshot]

No, water curing should not be done with water washable resin. You don't want your prints submerged for long and want them dried quickly. Water washable absorbs liquid at a fast rate which is why it gets a bad name for cracking.

[@DefaultProphet]

I’m pretty skeptical to the claim that uv light can pass through the water and get inside the model. Like if it’s a pretty open area sure? But like a drainage hole kind of situation? Seems sus