Washing with TPM & IPA

I thought I’d share my experiences on washing parts after they’ve come off the printer.

I used to wash them in very used IPA in the wash kit, then slightly used IPA, then clean IPA in a Form Wash so I didn’t contaminate the cleanest fluid. but it didn’t work very well - the IPA always got mucked up with (for eg) black specks on while objects, and became much dirtier than I wanted.

When I used TPM it left parts sticky, and whatever I did they stayed like that. So it wasn’t a solution on it’s own.

So lately I’ve bought another Form Wash and filled it with TPM. Parts get left to drain on some kitchen paper for a couple of hours, then put in the TPM for 20 mins. They’re washed under the tap, left to dry somewhere warm, and then washed in the IPA for 20 mins and dried again. This works very well - the TPM gets a bit contaminated, but lasts longer than IPA and doesn’t evaporate. So far after lots of washes, the IPA is still clean and parts come out very well. The process is much less faff than using the wash kit.

I did wonder about putting a UV source in the TPM wash to harden specks of resin and let them precipitate out, but haven’t got round to that yet. Has anyone tried it?


Hi nwalker,

We use both TPM (for commercial work) and IPA only (for medical orientated work).

Cleaning parts in TPM is good but a couple of things that we have learnt ourselves or taken advice from community.

We clean in TPM at 30 degrees C. Dirty wash followed by clean wash. We do use ultra sonics of 2 x 5mins per wash. We then rinse in warm water at 30 degrees C. 5 mins ultrasonics . We add 1/2 tsp of dish detergent to 1 litre of water for rinse.
We fling off water and then quick dip in clean IPA to absorb moisture. If we do not use IPA for a dip, the parts (TOUGH 1500) is sticky till cured.

We have dedicated containers for each resin wash to reduce cross contamination.

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Sorry to revive an old thread but I am about to fill up my 3L Wash with TPM and I have been reading all the pros and cons to IPA vs TPM.

I’m in a research lab environment and TPM is the preferred chemical, so I bought that.

After the print has drip dried, I was curious about using a spray bottle with IPA, while mounted in the Wash L, to hit it with a few sprays of that, allowed to drip dry/evaporate for 30 mins and then proceed with the TPM wash. Would that yield the best of both worlds?

I’m intrigued by your post wash ultrasonic ideas.

Hi LePaul,
We are still using TPM for our non medical work. Because our parts are very small with cavities we have extended our wash process as we found that some of our small and deep cavities retained some uncured resin that affected the LSR that came into contact with it. We design single use moulds for our prototyping work.
As the TPM is quite viscous when cold, we have increased our wash temperatures to 35 deg C to make the TPM more “mobile”.
We wash 3 times:
1st wash 5 mins in pulsing ultrasonics (degassing mode) removes most of the uncured resin stuck to the print.
2nd wash 5 mins at high ultra sonics in second beaker of TPM
3rd wash 5 mins at delicate ultrasonics in third beaker of TPM
As TPM is very miscible in water at 35 deg C with a dash of dish detergent
We rinse 4 times:
1st rinse in clean water 35 deg C with a dash of dish detergent in ultra sonics (degassing)
2nd rinse in clean water 35 deg C with a dash of dish detergent in ultrasonics (high setting)
3rd rinse in clean water only 35 deg C in ultrasonics (delicate setting)
4th rinse in clean water only 35 deg C in ultrasonics (delicate setting) This 4th rinse is to make sure we have rinsed thoroughly. for the sake of an extra 5 mins we save 5 hours in a LSR injected mould failing.
We then spin in a salad spinner and dry in oven at 50 deg C for 1 hour
We then UV cure when dried.
Seems excessive but we no longer have an issue with uncured resin residue in our moulds.
We no longer use IPA to absorb any excess moisture to reduce IPA consumption, but we still use IPA to clean our medical products.

I note that you use a Wash L. May be worth doing a coarse 1st wash in a prewash in a different container before the Wash L. Or use large US cleaner with big bowls immersed in water. TPM in the bowl.

No matter what industry you are in, cleaning is a matter of diluting the contaminants with progressively cleaner solvents (TPM, IPA, Water).

Do not use IPA in ultrasonic cleaner unless you have assessed the risks thoroughly!!

Hope that helps.


Yes I have the 3L, Wash L ad Cure L.

I won’t be doing medical prints but we will be doing high detail prints. This 3L augments my lab’s capabilities as we have several Ultimaker S5 3D printers.

I’ve read a lot of people’s methods for best cleaning processes.

What I came up with was after print has drip dried, place into the Wash L (but not lowered into it) and spray with 99% IPA and get those heavier blobs off. Letting this drip over the TPM and dry for 30 mins. Then, based on the resin specs, use the TPM wash. The next steps, remove support and cure per resin requirements.

BUT you have real time experience with these machines and you indicated using a clean water rinse. How do you dispose of this contaminated water?

I’ll pause there, awaiting your feedback!

What ultrasonic cleaner are you using?

Hi Lepaul,

The rinse water I evaporate off and the scummy residue goes into Dirty TPM waste container. I collect these for very infrequent controlled waste disposal.

I use the cavitek professional series from Allendale ultrasonics.co.uk. They come in all sizes and prices

To stretch the life of my TPM, when first wash looks “dirty” 2nd wash becomes 1st wash, 3rd wash becomes second wash and I get a fresh 3rd wash. Dirty wash is allowed to solidify so that I can drain off unsaturated TPM into 2nd wash.

Clear as mud!

Thanks for that information

Do you think our IPA spray / prewash will be useful?

Your idea will work. I use both solvents, but I don’t mix them.
Personally I would go for a rough first clean in TPM just by hand agitation. I am always wary of atomising IPA.
When cleaning TOUGH 1500 in TPM and rinsing with water The TOUGH 1500 still feels tacky so I have a quick dip in IPA to remove the stickyness and remove any residual moisture. That is the only time that both solvents are used to clean a part.
Just a thought… to reduce my dirtying load to the first wash I leave my parts on the build platform in the printer, hanging on a widget that holds the build platform at 45 degrees to drip into the resin tray . The heat from inside the printer keeps the resin viscosity low so it drips more easily. I have even orientated tiny hollow parts for maximum dripability and some times add drip features. Hang for a least an hour or what ever time you can afford. It saves resin drips and reduces cleaning solvent dirtying load.
I got this hanging widget off ebay or amazon.

The link didn’t show…is there a part we can print for 45 degree haning?

I noticed the left side hook to hang the build plate

My bracket was for an F2
Holder Draining Tool Drain Part for Formlabs (Form 2,Form 3) 3D Printer Platform | eBay. This was 3d printed. You have to check for a 3L in forum

Yes, I have looked around for a 3L Drain adapter and nothing comes up. I found something for the 2 and 3, as you linked!

Hi, has someone using TPM tried to expose to UV light a clear container of this liquid soiled with uncured resin diluted in it (coming from successively washing the parts)?
If so, does UV-exposed TPM allow liquid resin diluted in it to partially cure and precipitate as a “gooey blob” that can be separated and filtered out?

Why such question you may ask? To be able to recycle TPM in the Wilson Machine, thus considerably extending its service life.

IPA allows to do exactly this. However, it turned out that some alternative dedicated cleaners commercially available (e.g. the Resin Detergent from Sunlu, ResinAway from MonoCure3D… which are in fact solvents too and not “detergents” per se) totally prevent the diluted resin to cure and precipitate, meaning that these products cannot be recycled and must be disposed and replaced entirely when rendered ineffective :frowning:

Looking forward to your answer! If you never tried, may I ask you to run the following easy and cheap experiment using very little amount of uncured liquid resin (say, the equivalent of a resin bottle cap) poured into a small transparent glass container (about 4 oz) filled with TPM, expose it to UV light and report back here? I’d really appreciate it :slight_smile: