What to reuse or dispose of from large Form 2 cartridge/tank set?

I have recently become the caretaker and Main Guy In Charge ™ of a Form 2 and extensive set of resin tanks and cartridges where I work. I am only minimally familiar with the Form 2’s operation–I’ve done a couple of test prints early last year under the instruction of the guy previously in charge of the equipment–but otherwise there’s a lot that I don’t know yet about how to work efficiently with these machines.

I have about 10 resin tanks, a couple of which are LT, and all but one of which have various resin in them already. I have resin cartridges to match these, most of which have been opened (though kept closed/cool/dark). The opened cartridges and filled tanks have been opened/filled for over 12 months, and unused for at least 12 months. I believe the machine itself has been well-maintained and calibrated prior to the last few test prints, but it has been (carefully) moved from one location to another since then, so I’m not sure if another calibration is in order.

I also have a Form Wash, Form Cure, and a Finish Kit, with plenty of 99% IPA to go with it.

My instinct says the resin is probably unusable at this point, and possibly the tanks as well. I have read some comments that indicate the regular tanks can’t (or shouldn’t) be cleaned due to IPA causing the plastic to break down, while the LT tanks can be cleaned and reused, although I’m not sure if this is either simple or recommended–the tanks seem to be tagged with a single resin type once they’re first used.

So here are my questions:

  1. How much should I keep vs. throw out at this point?
  2. Should I recalibrate the machine?
  3. Should I clean the machine itself?

I’m going to need to print a few hundred small items in batches during the next few weeks, and I want to start the process the right way.

Thanks in advance!

Whether the resins will be ok depends largely on how they’ve been stored . I’ve got some resins that are dated 2016 and they print just fine so it’s definitely worth trying them out to see. The tanks might be ok but if stored with resin in them for any length of time the resin does tend to migrate under and lift the silicone layer on the non-LT ones.

You can clean the non-LT tanks, just don’t use any IPA (or various other solvents on them). I drain the contents of the tanks back into the cartridge using a funnel and paint strainer like these ones:

You can get these in various mesh sizes and I think 250 micron has been recommended, but it might be worth confirming that, although it’s not really that critical. I then wash the tanks with a concoction of my own making but you could probably get away with a strong solution of washing-up liquid (I think that’s called dish soap in the USA). I think most people just give it a good wipe out rather than going to the bother of actually washing them.

The first time a tank is used it will be tagged with whatever resin you’re using. However once cleaned out you can still use it with a different resin. The printer will flag up that there’s a mismatch between the tank and cartridge and give you the opportunity to reassign a different resin to it.

I’m not sure about recalibrating but I moved mine 20 miles or so in the boot (trunk) of my car to my home and it didn’t need anything doing to it. If it hasn’t been used for 12 months the optics might need a clean. I’d just do a few test prints and see how they come out.

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Here’s a good place to start: https://support.formlabs.com/s/topic/0TO1Y000000IvrlWAC/maintaining-the-form-2-form-2

Be aware the exact guidance has evolved over the years and you may notice some minor documentation discrepancies depending where you look.

In the LT tank article, Formlabs recommends against storing resin in LT tanks for more than 3 months. For long-term storage of dispensed resin, they recommend pouring resin into a separate, opaque container (e.g. wide-mouth opaque HDPE or polypropylene bottles).

In another article, they state Standard resin tanks (the ones with PDMS) last 1000-3000 layers of printing or 3 months, and that LT tanks should last twice that (which means up to 6000 layers / 6 months). There are exceptions for some of the more aggressive resins (e.g. engineering ones), where LT tanks are mandatory, and don’t extend the lifetime.

You can find general guidance on materials here: https://support.formlabs.com/s/topic/0TO1Y000000IvumWAC/materials-overview-form-2

And use the dropdown to read about specific resins (the “Using ___ Resin” ones are where you’ll notice specific guidelines / limitations).

All that said, I’ve personally stored various resins in tanks for over a year with no ill-effects (dark, room temperature, periodic mixing). If things have been sitting for a long time, it’s really important to stir them up well (using the metal spatula that has rounded edges, or a plastic one). The components can separate over time - e.g. I’ve noticed Black stratifies into a gooey layer at the bottom of the tank and less viscous one on top). If you’re patient and gently stir for long enough it becomes homogeneous again.

It sounds like the previous caretaker was meticulous, but it wouldn’t hurt to filter each resin through a ~190 micron paint strainer to catch any debris that might be left behind from previous print failures or partial failures (obviously use a new strainer for each different resin).

When you drain the tanks it’s also a good opportunity to inspect them for any visible damage, clouding or leaks (here are some photos). Any smudges or dust on the bottom (outside) of a tank’s optical window can be cleaned with a quick spritz of Novus #1 and a microfiber cloth. Avoid touching the interior of the window with anything but the spatula.

Never use IPA or other chemicals on a tank! It can cause the acrylic to crack or fatigue. As far as I know that also applies to LT tanks. Here’s a quick chart showing what products are appropriate for cleaning which components.

I’d also recommend shaking your cartridges for a good 10 minutes each. Shelf life of cartridges was increased a while back, I think most resin expires about 2 years from the manufacture date seen on the label, but some like Tough 1500 are shorter - you can find a full list here.

If dust may have collected, it could be worth inspecting and cleaning the printer’s glass optical window.

Since you don’t have a lot of experience yet with the printers, I’d pick up at least one brand new cartridge and tank to use for a test print. If you run into troubles, that will help you to quickly rule out old consumables / resin as a factor.

This page lists various print defects that can occur and how to diagnose and resolve them.

I’ve noticed over time, contaminants build up inside the optical chamber - on the main mirror, and sometimes even galvo mirrors. Dirty optics is a common cause of print issues (such as poor adhesion, ragging, etc). Before inspecting or attempting to clean the interior you’d need to contact Support. They can help you determine if cleaning is necessary (doing it too often can wear the first-surface mirrors) and provide official documentation on the procedure.

Once you know the printer itself is working, do a test print with each tank to see if the resin still produces good results (the built-in “butterflies” STL file is good for this and completes fast). I’d bet a lot of the resins are still completely fine. Of course if you don’t have time or want to be sure, and cost isn’t an issue, then you could always get rid of them all and buy new.

You’ll also want to top off the Form Wash with fresh IPA, or if it’s been sitting for a long time with dissolved resin in it, replace its IPA altogether.

You don’t need to re-calibrate after moving the printer. But if you want to, here’s some info on fine-tuning, and various users have created templates/models/spreadsheets to help (here’s one).

Here’s a great teardown if you want to know more about the internals of the printer without ripping your own apart: https://www.bunniestudios.com/blog/?p=4641

Finally, consider grabbing a copy of any of the above support articles that you find helpful (or snapshotting them with WayBackMachine or archive.is) along with any field guides you obtain from Support, before the Form 2 gets sunsetted in 2023. I noticed after the Form 1+ went end of life, a lot of the documentation disappeared from the website or became harder to find.

Have fun printing! The Form 2 is a great printer and fairly user-friendly.


Yeah the environmental aspect is a concern. I am trying to saved my tanks that have cracked bottoms in hopes to one day recycle them, though the cartridges I have no clue what to do. I would split it open to dry out though here in the UK we haven’t much sunlight to cure. Does anyone have a solution? Otherwise would be great to re-use the cartridge by having the resin in a much more eco friendly disposable container and just replacing the bite valve.

Also I got this IPA jelly from washing prints. Does anyone know how to dispose of this? The only way I can think is to break it up into smaller bits so it dries out quicker. As we have no sunlight here maybe some sort of big UV lamp?

Yes, I’ve got quite a selection of old tanks with cracked windows myself. I have replaced some but it’s quite laborious to break the bond between the window and the body of the tank and then remove what remains of the adhesive (it looks like it’s Cyanoacrylate) ready to receive a new window.

I’ve found these lamps to be really good at curing the resin in a few seconds so you could cut the cartridges open and solidify the resin with one of these. Alternatively there’s someone that will pay you for your empty cartridges (they reprogram them and then offer them for sale as a universal cartridge.

I’ve only had to deal with the IPA jelly once. We had put it into an old frying pan and left it outside for the IPA to evaporate off. This didn’t work as it seemed to form a skin which slowed the evaporation down to a standstill. I then poured boiling water over it as a safe way to boil off the IPA. Obviously this was done outside! It took a few kettle-fulls and some chopping up of the jelly but it reduced it to an easily manageable solid that could be disposed of easily.

great! thanks for the lamp link, I was looking for this type of lamp :slight_smile: I would much prefer sending it to be recycled, that’s a great option. Wish Formlabs would do this sort of thing, much better for the environment. Zvat also can recycle the tanks with glass base, though he’s based in the US which works out a bit expensive with postage. I will try to recycle the tank myself when I have a good space to work in. The silicone part looks the hardest as I would assume you need vacuum chamber and all that to de-bubble the silicone.

I’ve spread out the jelly into bits. It does solidify in the daylight, though takes a long time. The lamp seems the quickest option.

Check with your local authority, mine ( London, UK) has a scheme that will pick up domestic chemicals and recycle them.

You can burn off the IPA from the gel (outside, of course). This ends up as a pieces of cured resin that looks like a piece of burnt toast.

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Yes, the Z-Vat looks good but as you say: it’s expensive for us outside the US. I got some acrylic cut to size from one of the internet sites to refurb mine. Apart from actually removing the old one and getting all the adhesive out, the trickiest part is getting the new window glued in at the correct height and level. I have used Araldite 2022 rather than cyanoacrylate and I’ve not had any problems with it so far. You’re right about the siliconing. Luckily I’ve got a vacuum pump and a glass desiccator so I can degass the silicone before pouring it ino the tank. The silicone I use is Techsil RTV27844. I also paint some Momentive SS4120 Clear Primer around the inside edges of the tank as well as around the edges of the window to hopefully reduce the chances of resin seepage!

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cheers mrwakefield, some good tips there, will save the links for when I can eventually set all this up. I think this process will be inevitable if Formlabs stops producing resin tanks for Form 2. I saw the video on youtube and all that scraping off the glue business looked a bit of a tough job.

For now if anyone in the UK wants some used tanks with cracked bottom glass I’d be happy to send if you can cover the postage :slight_smile:

It’s actually much easier to convert a green LT tank as the window pops off easier. I’ve had great success glueing the cut-to-size window from ProtoART in this tank.