Alternate Wash Solution


#1

In the past, Formlabs advised using only isopropyl alcohol (IPA) to effectively wash liquid resin from stereolithography (SLA) parts and prepare them for post-curing. For more information, read our support article on isopropyl alcohol.

If you’re looking for other wash solvents for your prints, or if you’re just getting started with Formlabs SLA printers for the first time, we’re pleased to announce you now have a second option.

Formlabs has tested and approved tripropylene glycol methyl ether (TPM) as an alternative solvent to IPA for washing SLA 3D prints.

What is TPM?

Tripropylene glycol methyl ether is a colorless liquid with an ether-like odor. It has several advantages for cleaning 3D prints:

  • TPM cleans parts at a higher resin concentration more effectively than IPA.
  • Leaving parts in IPA for a prolonged period of time may cause warping or damage. This is no longer an issue when soaking prints in TPM.
  • TPM evaporates slowly and mixes well with water. It is non-flammable and has low volatility, making it a safer and more economical solvent than IPA.
  • While IPA may be difficult to procure in some regions, TPM is available globally.

Support Articles

Please visit support.formlabs.com to explore our support articles on tripropylene glycol monomethyl ether (TPM) and washing prints with TPM.

Read our support article on choosing the right wash solvent for an in-depth comparison of IPA and TPM and to find out which solvent suits your application best.


#2

I’m assuming that this endorsement of TPM also means that we can safely use it in the Form Wash?


#3

Any recommendations on wash times?

We use DPM in the form wash for 15 minutes, but requires extra cleaning steps(water rinse, then blow dry) and then let it rest before curing.

If we don’t do this there is a risk of damaging the form cure, high temp parts crack and there is a lot of warpage.


#4

Yes, TPM is safe for use in the Form Wash.


#5

TPM works roughly the same as DPM. The main difference is an even higher flash point and less smell.


#6

Does anyone have a good source for TPM? Did a quick online search and came up empty. I am located in the midwest US.


#7

I typically do 15 minutes TPM, 15 minutes water. Rinse bottle spray with water or IPA. Dry with compressed air.

Do make sure the parts are fully dry before putting into the Form Cure. (The same is true for IPA, but TPM and water evaporate much more slowly than IPA).


#8

Perfect, thank you.

It takes a bit of time to get used to DPM but when we got the flow right, our parts come out better(the surface is smoother than with IPA). We’ll try TPM next!


#9

Does anybody have a vendor to purchase TPM? Amazon search returns nothing. Google search does not return any vendors either.


#10

Are you using TPM as a liquid from the start or purchasing it in granular form and mixing it? If so what is the ratio for mixing you have been using?


#11

I don’t know where you’re based but you might have better luck if you search for Dowanol TPM. I’m sure there must be other manufacturers other than Dow but I’ve not found any so far. I know of a couple of sources here in the UK but it certainly seems much harder to get hold of than IPA.


#12

TPM is an organic solvent which is liquid at room temperature.


#13

I also have not been able to find a readily accessible source of Glycol TPM. So far the two brands that have popped up are Dowanol TPM (DOW) and Sta-Sol® PS 100 (HESS).


#14

Hello dear Formers, any advice about commercial products available in Europe?
Thanks in advance,
Mattia


#15

TPM is $325 per 5gal pail from JR Hess. They ship UPS or FedEx. Any less expensive options?


#16

I have their link bookmarked. My impression that what they sell is TPM based and optimized for SLA… given they have a specific product for SLA Resin solvents.

They have yet to get back to me with a quote, so thanks for the info! So does the low vapor pressure accomodate for the increase in price? Any other benefits for part quality? If not, anhydrous isopropyl is still cheaper… unless there is enough evaporating…


#17

I am not sure about PS-100 stuff that they have specifically for 3D printing. I looked at the SDS they sent me and it’s a mixture of PROPANOL, 1(OR 2)-(2-METHOXYMETHYLETHOXY)- (1) and PROPANOL, [2-(2-METHOXYMETHYLETHOXY)METHYLETHOXY)-. I am not sure how well it would work in Form Wash. Might be worth a try. The PS-100 is $375 per 5 gal pail so even more expensive. I emailed them to see if they will sell a gallon of each to compare.
I got everything (wash, cure, resins, tanks), just waiting on the actual printer. Tracking is showing that it’s about a day away. Once I get it all set up and if I get the samples I’ll post a comparison.


#18

I just got in contact with a BASF representative yesterday and asked if he has any sourcing. I’ll let you know if anything pops up.


#19

The support article suggest that the second wash can either be with water or IPA. If that wash were to be with, say, a 50% solution of IPA in water, would that give the best of both worlds?


#20

One of the benefits of DPM/TPM is that the surface is much more smooth than with an IPA wash. So that advantage will disappear.

However, if you’re fine with the finish using IPA, it can still help a lot prolonging the life of your IPA bath. Sometimes we do this anyway as the parts dry much faster after an IPA wash.