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How do I clean this? If I have to


Glad to join the Formlabs community finally. A real quick question is how do I clean the glass underneath the tank? Is there any special film on both sides or just a glass?

If I have to clean it someday, what do I need to prepare? Is there any good liquid cleaner?


IPA (official recommendation) or acetone (if you know what you’re doing -> the foam around the window doesn’t like acetone), both as pure as possible… plus dust-free cloth (pec-pads).

If you need to clean both sides there are two easily accessible screws to remove the window, Formlabs support can provide you with a pdf guide on how to do that if necessary.


Only use IPA to clean off any resin spills. Use Lens Wipe Tissues (non-IPA type, ZEISS are the best) to clean and polish the glass. This will leave it streak free, the IPA won’t. This from experience.

If you’re talking about the stuff on the sides, that’s probably just glue and shouldn’t be in a location where it will interfere with the laser.

Great!!! Thanks.

Thanks. @Walter

I work with lasers and optical surfaces, so I have experience in this kind of stuff as well and not only cleaning the Form 2 but some way more sensitive surfaces. Acetone and optical cleaning pads are the way to go, unless the surface you’re cleaning can’t take acetone (Formlabs’ mirrors and glass show no issues in that regard), in which case another quick drying solvent is recommended.

The main reason why Formlabs doesn’t recommend anything else than IPA, I think, is that it’s the least risky solvent because it can’t damage or dissolve anything on the printer except the orange plastics but even then a small quantities of IPA won’t cloud it or anything.

See this page for more details (in particular the “Drop and Drag Method” which is the best method to clean the galvo mirrors in my experience :

I tend to use IPA when there are big things to clean, but I always finish off with a drag and drop operation with acetone.

Same here. We clean high power laser optics for our laser welders with acetone. As well as the formlabs mirrors and windows. It just works so much better than IPA and doesn’t leave any streaks. The less we have to wipe, the lower the risk for any scratches. But yeah, be careful on any plastic!


How does acetone work on the resin trays? I have almost a dozen I’m going to start recoating and will need to clean them of any resin residue. Had planned on using ethyl alcohol but acetone is cheaper I believe.

I wouldn’t use acetone on the resin trays, those are not glass but acrylic :wink: This is exactly why Formlabs doesn’t recommend acetone for cleaning the parts that support it : because people will use it on things that don’t.

EDIT : to be clear, PMMA (acrylic) is dissolved by acetone, while PC (polycarbonate) doesn’t but it will have a limited life and absorb the acetone so usage isn’t recommended either. I’m betting the underside of the tank is either PC or PMMA.
The inside film is probably resistant to acetone, but the glue joint most likely isn’t and the risk of damaging it and the consequences of that make it not worth it in my opinion.

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Never let IPA or acetone close to the tray. Both acetone and IPA damage the acrylic window.

If you want I can sell you some borosilicate glass cut to size so you can replace the acrylic.

Ethyl Alcohol has been recommended by ALW to clean the resin trays. That doesn’t affect the acrylic plastic from what I’ve been told. That’s what the Zeiss Wipes have been saturated with.

Don’t use ethanol, acetone or IPA on acrylic.
Here is some info:

It can potentially crack your acrylic. The orange polycarbonate is safe for IPA and ethanol.

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Plenty of “DON’T DO’s” but what CAN be used to clean resin off of the resin trays?

For the acrylic itself: water and soap. That’s why people who recoat a lot replace the acrylic for glass. It enables you to clean everything with IPA or ethanol

I thought the Orange plastic was the acrylic, not the clear panel in the bottom of the resin tray.
Warnings have been out not to wash resin off the orange plastic with IPA as it will fracture.
So, which is which?

I think I said this before: the orange is polycarbonate. The clear window acrylic.

I clean the orange part with IPA, no problems there.

Acrylic can’t handle much, not even uncured resin. I have had the window crack when there was resin on it.


A very interesting link on optical element cleaning. Thank you for posting.