Isoprop care?

Hi there.

Are there any science boffs out there who know how to filter resin out of isopropyl? Due to being in a wheelchair I have the Form Wash, I cannot afford to get resin all over the chair, that’s just no fun. However, this means I have a 10l tank of Isoprop which needs to be thrown away from time to time. I suppose this is better than flushing it straight down the sink manually washing objects, still it seems wrong. It would be nice to pop something in the tank to attract the resin and pull it out.

UK guidelines for Isoprop handling are simply tip it down the drain, which I don’t like either. What do you other folks do with the old stuff?


The resin dissolves into the IPA. The only way of separating them is by distilling with a still. There are a few threads on this forum from people who have successfully done it.

Pouring pure IPA down the drain, in the amounts we use, isn’t an issue. The issue is that IPA isn’t clean and uncured resin can’t be poured down the drain !

As said, distillation is the only way.

Otherwise, you should really put your used IPA in a bucket and get it to a place where they accept used up solvents.

To avoid pouring out the relatively heavy Wash tank, it can be handy to use a siphon or some kind of manual or electric pump to transfer the dirty IPA into one or more closable containers. Then any sludge at the bottom of the tank can be wiped up and disposed of as solid waste before refilling the Wash with clean IPA.

As for the containers of dirty IPA, you can hopefully arrange for a local hazardous waste handling company to come collect it when you’ve got enough. If it’s small enough amounts, you might find that some municipalities and local governments will have programs for collecting hazardous waste that might take your used IPA.

There’s been discussion in other threads on this forum about methods of curing the dissolved resin in the IPA and/or separating the uncured resin by adding water to make the resin precipitate out of solution from the IPA, but I don’t think any tried and true method for handling a whole Wash tank worth of IPA has been developed out of those investigations yet.

I’ve only had to get rid of one lot so far when the IPA had so much resin in it it turned to gel in the wash station bucket! Initially I thought I’d put it into an old frying pan and just leave it outside for the IPA to evaporate off but it got so far and then didn’t seem to be losing much more. I then poured boiling water over it to boil off the IPA (yes, I did this outside!) until the resin formed a solid that could be put in the bin. This worked quite well but in future I’ll have a go at recovering the IPA by distilling it.

Luckily my local tip will take nasty oils and other chemicals, they’re sat right in the middle of an industrial site so I guess they get a lot.

I may well try the distilling when I get the workshop up and running properly, I’m still waiting for the bricks!

All very interesting, thanks folks.

I have noticed that adding some Yellow Magic 7 (YM7) to the IPA in the Form Wash will cause the dissolved resin (only tried with FormLabs Grey v4 / Black v4 and ApplyLabWork equivalents) to precipitate out of the IPA solution. Have not experimented to see what is the minimum amount of YM7 to use (it’s a very small amount), nor do I know how to get the YM7 out of solution with IPA.

Once the resin is precipitated out, and letting it stand to allow gravity to get it all to the bottom, just pour off the IPA/YM7 solution and then clean the resin out. Then re-use the IPA/YM7 solution for more cleaning.

Are you sure it is the resin and not just the pigments in the resin?

The pigments will settle out of plain IPA if it is used enough.