Isopropyl alcohol (IPA) acts as a solvent for 3D SLA printing resin, but the resin will still solidify if exposed to UV light in the wash vat.

I pour the IPA and fine resin into a tall tube (siltation tube) and allow gravity to separate the IPA from the solidified resin (which falls to the bottom of the tube).

By emptying the resin (and some IPA) using the valve in the bottom of the tube, I can separate most of the resin into a graduated cylinder (or two). I can then let this settle again over a day or two and pour off the resin from the top of the graduated cylinder (being careful to NOT pour the resin back into my wash vat).

A small amount of IPA is thrown out with the resin silt, and the vat is topped up back to the max fill line, but most of the IPA is recovered.

This longer video goes into more depth:    • Summary: Removing UV cured resin from...  

I built the tube in this even longer video:    • Experiments with removing 3d printing...