I went to wash a recent print and saw that the ipa tanks looked weird. upon further investigation I begin pulling handfuls of congealed goo out of both my ipa baths. What is this, and what caused this?
IPA will remove the resin on the outside of the print but it will still accumulate in the IPA over time. If you’ve done a ton of prints and haven’t replaced or filtered your IPA then you should do that. It’s not something you can keep using forever. You can try filtering with a paint filter or a paper towel and that will help.
That does look weird. Hard to imagine the IPA was very effective at cleaning parts if it was that heavily loaded with dissolved resin. And it doesn’t explain why it would semi-solidify. Unless for some reason the IPA tank was exposed to UV, like maybe from a nearby window. But even then… I routinely put my IPA tanks in the sun for a couple of hours. It cures the dissolved resin, but it doesn’t gel, it precipitates out as a fine “powder” at the bottom of the IPA tank. I can then decant the IPA, rinse the residue from the tank, and then pour nearly-good-as-new IPA back in to the tank. I’ve had IPA that had been used enough it was noticeably more viscous, and it didn’t turn to gel when I put it in the sun.
I had seen on other posts some level of precipitation, nothing as solid as mine however. Even more weird is that i had run all of the IPA through 190 micron paint filters only a few weeks before.
The tanks are directly next to a large window which gets a lot of sun, this large amount of UV light could be the cause (I have since moved the tanks).
Still very weird though.
The few times I’ve put my used IPA in the sun, the resin turned to a layer of gel at the bottom just like this. The IPA above it was good as new. So I would second the suggestion that UV is hitting the IPA tank somewhere. Not sure what the variable is to differentiate the resin settling out as powder or gel, except Randy says he leaves his out for some hours and I usually do it for a day or two. Randy, when you say your IPA becomes nearly new, does that mean it will no longer leave a sticky film on your skin when it dries? For me that is the test of whether the resin is sufficiently out or not. When it “gels”, the remaining IPA is as non-sticky as new. Maybe gelling is a later stage after precipitating…
Hmmm. I haven’t been tempted to try letting the IPA dry on my skin. But no, I doubt it’s tack-free. It’s just much clearer than it was before.
I print almost exclusively with Tough. My print area is not very brightly lit. When I can’t see the basket at the bottom of Wash Tank 1, I put the tank in the sun for an hour or two and I end up with precipitate at the bottom. I decant the IPA, clean out the precipitate, and pour the IPA back in to the tank. I’ll do this until Wash Tank 2 starts to get a bit cloudy. Then I dispose of the IPA in Tank 2, refilling it with new IPA and swapping it around with Tank 1.
I generally put a couple of liters of prints through the two tanks before I need to purge the oldest stuff.
Also, I don’t know if this helps, though it might… I always agitate the prints while they’re in the IPA. I think this makes Tank 1 much more effective and in spite of the IPA left on the prints having a high resin concentration, I carry less resin to Tank 2 because the parts are “scrubbed down” and as a result the IPA in Tank 2 lasts longer.
Randy is right, uv light will cause the dirty ipa to cloud and get lumpy. Most likely that is the cause.
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