Alternate Wash Solution

#82

I use TPM on TOUGH 1500. It is effective. We use a 3 stage TPM wash in jam jars sitting in an ultrasonic cleaner. We use it at 30 deg C and it makes a difference. We then rinse in warm water with fairy liquid dish washing detergent,

You are right it takes for ever to dry and does feel waxy to the feel. We were concerned too, but now we do a final rinse in IPA not to clean it but to absorb the moisture, Then dry as per ipa wash and cure, No waxyness or stickyness. This extra step saves a lot of drying time and the ipa is effective for a long time.

Filing and sanding leaves a silky finish.

#83

The soggy noodles I was experiencing was traced to the prior firmware updates on both of my Form 2’s. The latest firmware seems to have fixed that issue.

The waxiness is definitely something that seems to be surface related. The surface of Tough 2K looks like light grey instead of the dark grey it should be. If I rub my thumb lightly on the part after washing and rinsing, I can get marbles to form which stick to the surface of the part and expose the darker plastic underneath.

While I can cure a part like that, and it comes out fine after being cured, the finishing process becomes more difficult. IPA drys within a day and can be handled and sanded without issue prior to a full cure. While I can wet sanding uncured TPM washed parts, and it sort of works, if any marbles are created and cured it becomes difficult to remove those marbles afterwards and makes the surface very rough.

The reason I like to sand before curing is because of support cleanup. It is far quicker for me to remove support marks when the item is not cured. With IPA it was wash, dry, wet sand, and cure. With TPM, it is wash - try not to handle with bare hands or bump parts together, dry, cure, and wet sand for 3x as long. In my workflow, sanding post cure tends to damage edges and other geometric features while trying to get the support nubs sanded off.

With TPM, the overall tackiness of the surface after washing is the big issue for me. I like your idea of post washing in IPA, but the point of trying TPM was to eliminate IPA from my workflow. I’ll try dunking the parts in some IPA after washing and see what that does. I was kind of hoping I could eliminate IPA altogether.

20200720_125817-0000

#84

I am intrigued by your wet sanding. I’ll have to experiment with that. Thanks

Yes the surface is soft, we have scratch some parts when fishing them out of TPM, especially the first wash as that is the murkiest! Yes it is slightly darker underneath the surface.

Our move to TPM was driven by the price of IPA exceeded that of TPM and availability was poor for a couple of months back. We still have to use IPA on DENTAL SG and future biocompatible resins. The TPM is used on our more commercial components.

So we cannot phase out IPA for now. My normal IPA supplier still has no stock for sale but I found an industrial supplier that helped out. They also sold TPM so one cheap delivery cost

BTW formlabs now sell TPM. I think it is qty of 5L

Good luck with your dunking!

#85

Would it be possible to arrange a setting in the Cure which would quicken the DPM/TPM drying time?

I would prefer to remover the supports before doing a full cure, so having a ‘surface’ cure would help.

#86

I have picture of someone who tried to dry wet parts fresh from a DPM bath and it damaged the mirror coating of the form cure. Best to rinse it off with water or ipa as last step and let it dry a bit before you put it in the form cure

#87

Re: Damage to Form Cure
We noticed clouding on our Form Cure too after switching to TPM, but have never placed parts wet into it. I think it was coincidental that we noticed it. It wasn’t on the surface either, it wouldn’t come off with soap and water or even IPA and other thinners. In the end, we had to buff it back to life using automotive restoration polishes.

Re: TPM + IPA
We found the best solution was the one offered by @greymatter. We finally acquired some 99% IPA and the TPM + IPA wash works well. The parts are drying to the touch quickly with no stickiness at all, and we can easily wet sand them within one hour, and sometimes less.

We wash Tough 1500 or 2000 in the TPM for 20 minutes, then 10 minutes in the IPA. It certainly stretches the IPA this way. After 30 full tray washes my IPA is still clear while the TPM is a solid grey.

The TPM has shown no signs of evaporation after almost 20 days. My IPA leaches about 8 oz a week even with a rubber seal around the lid of the Form Wash. The Form Wash with the TPM has no rubber seal added.

Given that the cost of IPA is ‘down’ to $160-175 for 5 gallons, and 5 gals of TPM cost me $335 shipped, I think we will probably just go back to a pure IPA wash.

#88

Wow, that’s a lot of money for 5 gallons of IPA. I think we usually pay $20/gallon, but also haven’t ordered IPA since pre-pandemic.

https://www.rshughes.com/p/Loctite-C-2546371-3D-Printing-Cleaner-Liquid-18-Kg-Pail-LOCTITE-2546371/loctite_2546371/
I would give this stuff a shot before giving up entirely. This seems to be lasting at least 3x what IPA did and the 10 second post IPA wash we do is going to last for ages. Anything that reduces my solution changes and reduces hazmat disposal is ok in my book.

Other alternative if you are going through tons of cleaner is to distill the IPA. You can buy a distillation solution for less than $1k but you’d have to be using a lot of IPA to make it worth your time and money. This would also reduce hazmat disposal as well.

#89

Yeah, $20 per gallon is long gone.

That Loctite stuff is really hazardous. It has a combustible hazard rating of 4. IPA is 2 by comparison. Do you use this in a Form Wash?

#90

CAT 4 is better than CAT 2. Worst is CAT 1.

Yes use it in Form Wash, no issues so far.

#91

Obviously I flunked safety training


#92

No worries I had to look it up myself. Most, myself included, probably think of the NFPA square where a higher number is worse.

#93

That loctite stuff is just pure Di(propylene glycol) methyl ether.

It lasts a long time and if you buy it without the loctite brand it will probably be cheaper. We buy it in 20kg drums. It lasts a lot longer than IPA and is safer to use.

A lot has been written on this forum on DPM already.

Be careful that it can dissolve the black coating of the form wash. Our machine still works fine though after 1 year of use.

#94

Yes, heard it’s just rebranded DPM, but I’m no chemist. Do you have a supplier where you buy 20KG drums?