As you wash finished prints with IPA/Ethanol, the uncured resin will be stripped off and mixed with the alcohol. As time goes on, the alcohol will be saturated with more uncured resins to the point where it becomes counter-productive to wash in it. Here is how to make the best use and dispose of dirty alcohol with resins.
Use it as the first wash.
It is an excellent practice to have two buckets of alcohol, one is dirtier, and one is clean and fresh alcohol. The purpose is to use the cloudy alcohol to do the first wash to remove most of the uncured resin before moving to the pure batch for the final wash. This will make the alcohol last longer by keeping the clean batch fresh and having a way to use dirty but still usable alcohol.
(Note: PS: The picture comes from VOG video, link youtube.com/watch?v=5U1IshPqmak)
At some point, the dirty alcohol will be so cloudy that you can no longer use it to clean effectively. You will have two options. Recycle if your alcohol is IPA or dispose of.
Recycling IPA
You can consult the excellent video by VOG
Disposing
Do not dump dirty alcohol into sewage! It can have devastating on marine lifeforms!
The proper way and most energy efficient to process IPA/Ethanol is to let it evaporate via sunlight. This will cure the resins in the alcohol while removing the alcohol. Please do this outdoor, not in an enclosed space. Do not try to boil the dirty alcohol. It is not a safe practice. For places that do not get much sunlight or during the Winter season, IR light can help remove the alcohol quickly.
2 comments
Troy Telford
My brother is a chemist, and I asked about distilling wash alcohol. His advice to me: Don’t. Even if I don’t burn down or blow up, I’m left with a vat of much more toxic sludge to deal with on the other end, and very contaminated equipment.
Professional chemists just barrel their HAZMATS up and let the professionals take care of it, and he told me to do the same. He then pointed out that my city accepts ‘household amounts’ for free.
Buying a few liters of fresh alcohol is not free, but neither is my health. As a bonus, fresh alcohol hasn’t absorbed water from the air. The old alcohol is definitely more than 5% water.
Earl Hackett
There’s no way I’d distill a flamable liquid with that setup in the videol
Home Depot offers a VEVOR
3 Gal. Wine Distiller with Condenser for $85. Stainless steel and copper tube construction.