Does Resin-IPA-Liquid degrade?


#1

This may be a stupid question, but I did not use my Formlabs Form 2 for more than 1 year. In the basic wash station, there is still a mixture of resin and IPA. Since I placed a little weigth on top of the wash bottles, only a little bit of the liquid did evaporate.

Now the question:
Can I use the left over liquid in the wash station? Is it maybe more toxic than before? Does the resin in the IPA change in some chemical way after all this time? Just asking. Thanks!


#2

The resin that’s left in the IPA eventually precipitates out and settles on the bottom. A common method of recovering IPA for continued use is to put the wash bucket in the sun for an hour, then wait overnight, then pour off the clean IPA with only a little bit, with the precipitate, left over in the bottom of the bucket that you have to get rid of. Done right, you recover maybe 98% of the IPA. And what you recover is perfectly good, never goes bad. You’re all set.


#3

Thank you for your answer. So the resin-IPA-mixture has not changed chemically? I do not have to clean the wash bottle like if there is something rotten in it before I reuse it? Maybe I am just overly careful.


#4

The IPA and Resin don’t chemically react. The resin is “in suspension” in the IPA. Remove the resin from suspension, the remaining IPA is just as good as before the resin was mixed in.


#5

Nope, the resin dissolves in the IPA, much as sugar does in coffee. The IPA can always be released by distilling.

The ‘set the IPA in the sun’ method will only work if there is relatively little resin dissolved in the IPA. Once a certain volume of resin has been dissolved putting the IPA in the sun will form a solid gel that fills the container. .


#6

Regarding Randy’s comment that saturated resin becomes a solid gel, this hasn’t been my experience. Perhaps it is temperature dependent.

I’ve left saturated IPA in the sun when it’s only a few degrees above freezing, and it did not form a solid gel. The resin became became sort of a web-like gel, with lots of little holes. That allowed the IPA to filter to the top, and the resin gel to sediment at the bottom.

Perhaps the cooler temperatures makes the process slower, allowing little channels of IPA to separate everything out.

I think the “leave in the sun” method does not work with all resin types. Some of the engineering resins do not appear to separate out completely with sunlight.


#7

The question is how saturated does the IPA have to be to make the gel form?

I’m thinking fo a work flow where after X washes 5 litres of IPA is taken from the Wash and placed in the sun to clean, while the Wash is topped up with fresh IPA. This might be worth while if X was a largish number, say related to the number of washes done in a week or two, but not if it were to be smaller.


#8

If your IPA is saturated enough to turn to gel in the sun, you waited way too long to clean your IPA. Once the IPA is cloudy enough you can see that it’s obviously cloudy, it’s time to clean the IPA. The amount of resin you can remove is a function of how saturated the IPA already is with resin. Once the IPA is completely saturated, it puts as much resin back on the print as it removes…