Post curing in water, or dry


What are the pros and cons of post curing in water? Is it worth it or is curing dry just as good?


Strictly speaking, water doesn’t cure the resin. Only exposure to UV does that. Water can help rinse solvent/resin residue off, but I don’t think would be much benefit of soaking the parts while exposing them to UV - it would probably just hinder the process.


Curing in a water bath can help increase surface hardness. It works because water contains considerably less free-roaming oxygen than air does. Air contains about 20% oxygen, but water contains less than 1% dissolved oxygen. Oxygen can inhibit radical polymerization of UV curing resins, leaving parts feeling tacky to the touch.

Water does absorb UV light, the absorption is not significant at the wavelengths used to cure UV resin. So you don’t have to add much exposure time if you cure your parts in a shallow tank of water.

There are really no “cons” to curing in a water bath, other than getting your parts wet and require drying. You should give it a try and see if it improves the surface hardness of the parts you’re printing.


I always cure under water because it speeds up the curing time and gives great results.

Here you see the printed objects in a jar of tap water in the middle of the curing chamber.


I did not know that! I’ll have to give that a try. :slight_smile:


water helps a lot and it is our recommended way to post cure. it speed up the process by couple times over and the print has a clean finish.


I once tried curing underwater and while it helped curing a lot, it introduced “bubbles” on the surface finish which I guess they were there already (air bubbles in the water).

Is distilled water any better or no dfference at all?


Curing under water do generate bubbles on the surface of the objects but I have not noticed any negative effect on the surface finish.


we have not notice any difference. We usually just throw it in a Ziploc bag and blast away with UV light. works well with minimal water usage.


Very very very little difference, as the distilled water has less suspended solids in it, but not worth using.


I actually just had this happen, extremely badly. Chicago water is notoriously cloudy from the tap (warm water) then becomes clear, but I apparently didn’t let it sit enough. I cured for 10min as I usually do in water and HOLY COW my pieces are covered in bubbles. It’s like I made them out of sandpaper. I need to let the water sit for a while it seems.


Try adding an aerator to your tap. It should help clear up the cloudy water much faster.

I always get my highest quality parts by thoroughly washing in an IPA bath with dish soap and a toothbrush, then rinsing the IPA off with soap and water, and then dropping the part into a vat of fresh tap water for curing. I always dump the rinse water and curing water after each batch of parts to avoid any floating resin particles from adhering to the next batch.


Try something like this. You fill the vase with water, and it dramatically lowers curing times.

DIY Curing Vat


The is a stl designed for our UV led. You can fill water in the lower chamber.