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Stupidly simple solution to the form wash evaporation woes

My Form Wash was losing a liter of isopropyl alcohol every week and it made my office stink (the wash is right next to my desk) so I found a not-so-elegant solution that’s actually been great. I drain my Form Wash after each use.

This is fine for my print frequency since I’m only doing 1-2 prints a week. I wash, then use the included pump to get most of the iso into the carboy, then pop the tank off the wash and tilt it to pour the remaining iso into my carboy. Now one fill of the tank has lasted me months instead of weeks.

The McMaster part number for the 5 gallon carboy I use (pictured) is is 43005t3. The 2.5 gallon carboy (45005t2) will empty the tank no problem but I like the extra capacity and I typically keep 12 liters (16 bottles) of iso in the carboy so it will not get diluted with resin as quickly.

Edit: there may have been a slight exaggeration on the iso loss. That said I needed to top it off almost every wash which for some reason was more annoying than draining/filling it.


Do you use it A LOT? I’ve filled it completely only ONCE and refill just a few ml every week or so!? ALso no stink unless you leave it open after a wash, of course.

Is there some kind of seal that can be applied to the door at the top? a rubber damper perhaps to prevent the smell from escaping? Sounds like it is the smell that is a bigger issue rather than the loss of IPA.

Formlabs said they tried a version with a seal during development and that it didn’t had an impact on IPA evaporation… I find it a bit hard to believe but since I do not have a Wash I can only trust that they did their best

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Why not just put a plastic bag over the Form Wash?

I actually like this idea. You could filter each time you refill.

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@bolsoncerrado I noticed a loss of about a liter per month which is by no means a big deal but since I only fill/drain once or twice a week it is just easier take a few minutes to drain it and to lose next to nothing. When I first started doing this I had exactly one tank’s worth in the carboy and could monitor how much I was losing. Even after about ten washes over a month I didn’t need to add a drop! Before I started doing it I was losing about a liter a month!

@Walter_Gillespie That’s not sexy enough for me :slight_smile:

Now if I could just figure out how to make it quieter than 1 million mating mosquitoes…

Ugh. While this is a nice hack, I can not believe this is the solution.

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Does good ole fashion plastic wrap help?

@shawny2005 yeah it’s a small inconvenience but this issue is nowhere near as bad as the noise. The whole office gets blasted with a high pitch ringing that’s incredibly annoying. You don’t want to be in the same room as this thing.

@momentif I’m sure it would but that seems wasteful and looks much worse than using the tank in my opinion

Stick a filter on the pump intake to catch the solid bits and now you’ve got an IPA cleaner! Paint strainer on the end of the line might also work.

I empathize with you. I wrapped my Form Wash in a clear plastic bag and twist the end closed when it’s not in use.

It may not be scientific, but I know it has some effect - the label on the front of my unit used to be held on with scotch tape, but when the bag was closed for several weeks the IPA vapors actually ate away at the tacky adhesive in the tape and it peeled off.

Starting today I think I’ll try just putting saran wrap over the bucket opening:


You can take the tank easily. without the pump even.


1L / week seems like an awful lot. I’m only losing a few mL per week, and only smell IPA when the lid is open.

@Rodrigue I’m well aware! As I said in the post I leave it in place, pump it out, then I pop the tank out of the wash and pour the remaining into my carboy

@Amanda1 as I mentioned in the edit that may be an exaggeration (probably more like 1L/month) but it was still enough to warrant constant topping off. My wash is about two feet from my nose when I’m at my desk so it became quite a nuisance.

Over a few weeks of no printing. I lose about 2" from the mid line of the recommended height. Thinking about printing a cap on my FDM printer and on the inside having some sort of seal. Removing the IPA isn’t a bad move but I’m lazy lol. I need it to be ready to rock even if I only print once a week.

For the people with high evaporation rates is it like 95F in the room you have this in? I don’t understand how there could be this amount of loss just due to evap. I’m 5 months in with our Form Wash and i add a liter once a month and attributed most of this loss to what comes out on the prints and evaps off them. We are averaging about 3 prints a week, was one or two a day for the first month. If you are losing a liter per month i think there is something else wrong here. Is the trap door that closes when the rack is full up closing?

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My place in the summer is at 82 on the regular I’m in Chicago

I lost about 1.5cm of IPA in two weeks.

Definitely won’t work for me without a gasket…

This works for me - simple and cheap solution

Fails after around 6 months but they are real cheap to replace - elasticated so it forms atight fit around the Form Wash


hahah bro fist :fist_right::fist_left::muscle::muscle::muscle::grin: