We recently did some very thorough testing with alternative solvents, and came up with TPM (Tripropylene Glycol Methyl Ether) as our approved alternative to IPA. It has an extremely high flash point, is compatible with Form Wash, and can dissolve >3x the amount of resin compared to IPA. Depending on the quantity bought, it ranges from 1-3x as expensive as IPA up front, but it ends up being cheaper to operate than IPA in most cases because of the increased resin capacity and lack of evaporation. You’ll want to wash the TPM off with water (not down the drain) as it won’t dry at room temperature in any reasonable amount of time. You can check the Dow website for distributors.
DPM is also compatible with our resins and works well, but has a lower flash point and has some compatibility issues with the powder coating on the Form Wash.
Let me know if you have any more questions or comments. We’re continuing work in this space to improve the wash experience and feedback is always helpful.
Form Wash with anything other than IPA?
That is great information thank you. How is the smell of the TPM, does it have a strong smell like IPA or is it a more tolerable smell?
The smell is different, but generally less pungent as TPM doesn’t evaporate much. If you’re using Form Wash, you won’t get that strong blast of vapor when the part comes out like you do with IPA. TPM and DPM are similar in this regard. Is smell your primary reason for looking for alternatives, or something else?
Smell is a large part of it for me, but honestly what led me down this investigation was a YouTube video. A maker was testing out cleaning agents (Mr. Clean, Simple Green and Mean Green) to clean off resin prints (made on cheaper printers with Elgoo resin). He seemed to get better results for less money with the cleaning agents than IPA so I wanted to see if anyone had tried it with the Form Wash since I have one of those for my Form 3 which is on the way.
This was my experience as well. I even emailed them, they gave me some line of BS along with a few suggestions that I have yet to try because I can recognize smoke and mirrors when I see them.
The product sucks.
I tried DPME, but didn’t like it. It cracked the plastic housing on my ultrasonic cleaner. Some resins, in particular durable, seem to absorb it more readily than IPA and distorted. I also sometimes left a film of resin on some, mainly flat, surfaces.
Maybe, though, it just needs to be used in a Wash rather than open buckets.
I only use it in the form wash and ultrasonic, not in the bath supplied with the printer. This goes well with even high temp resin, which is prone to crack when it sucks up too much. My ultrasonic cleaner is stainless steel so never have issues there. It works different than IPA as it doesn’t seem to dissolve the resin like IPA does but removes it from the surface. We have no trouble combining rigid resin with all the other resins in the same form wash, which is a no-go with IPA(leave white residue). We print a lot with durable resin without issues for months already.
The Tripropylene Glycol Methyl Ether is a good suggestion and I’ll order some to try next.
New Form 3 owner here (anxiously waiting for delivery).
My company has very strict safety rules and thus we’re going to have to use TPM instead of IPA. I have two questions about TPM:
- What’s the procedure for monitoring the saturation of the TPM with the hydrometer? Or is that even possible?
- You mention that the evaporation rate of the TPM is much slower than IPA. How much slower? It will not be possible for me to rinse off my parts with water after coming out of the wash. I’ll have to wait for it to dry.
Thanks.
TPM has a specific gravity of 0.965. Our resins are around 1.1. We’ve found that TPM saturates when resin is around 25% by volume of the mixture. The other way is to wait until the TPM loses efficacy. It lasts quite a long time so it hasn’t been much of an issue in the office yet.
TPM basically won’t dry at room temperature. What is the reason that you can’t use a water rinse? DPM is generally compatible with our resins and will dry faster than TPM, but isn’t compatible with the Form Wash, still won’t dry that fast, and has a lower flash point that TPM. What is the reason you can’t use a water rinse?
@tech_nickl could you link to a place to purchase? I’m having trouble finding TPM for sale online…
What are your (or anyone internal at Formlabs) thoughts on using Yellow Magic 7? Are there any reasons you’d not suggest this for the Form Wash or using it in general with Formlabs resins?
Could you also comment on the benefits of TPM vs DPM?
The easiest way to find a distributor is to go to the DOW website and request distributor information for your area. I haven’t found it for sell outside of a distributor yet.
https://www.dow.com/en-us/contact/products
In my testing of Yellow Magic 7, it worked ok in an ultrasonic cleaner. The specifics will depend on what ultrasonic cleaner and resin you use. It is not compatible with the Form Wash and doesn’t work well with plain agitation anyway. We also have not tested material properties (tensile strength, elongation, etc.) when parts are washed with Yellow Magic 7.
As for a comparison, the main differences are that TPM is considered non-flammable by GHS/OSHA (check your local regulations) and is compatible with the Form Wash. DPM will bubble the powder coat on the Form Wash.
DPM will dry a little faster, but way slower than even water. I have seen DPM on Amazon before, so it may be a little easier to procure.
We buy our dpm from a local distributor. In bulk(20 liter container) is much cheaper for us, like 1/3th of price compared to liter bottles.
I think we now put 3 or 4 liter of printed parts through the form wash with dpm and it hasn’t saturated. After about 2 months we still don’t have to top up the formwash which is impossible with ipa.
And yes, the coating of the wash and platform has disappeared… but machine works fine still.
@tech_nickl how long do you do a wash session? We do around 10 to 15 minutes, then rinse in hot water and then spray dry.
Another plus: we used to need different buckets for rigid and standard resins otherwise rigid particles would ruin our parts. This is not needed since we use DPM.
We also buy locally, cheap and easy to get…
TPM is even cheaper and great in the ultrasound bath (Its not as quick as DPM)
Has anyone tried this? (Link on the website of JR Hess) It seems they have put together something specially for 3D printing
@tech_nickl Thanks for your response. Glad to hear that TPM is lasting a long time in your office. The longer it lasts before we have to change it the better. It’s beginning to sound as if we will need to do a water rinse after all. It’s not that we can’t do it, it’s just that it’ll mean more chemical safety/disposal procedures be put in place. Around here everything has to be done by the book. We’re actually really lucky that we were allowed to have a cleaning station in our lab in the first place.
Thanks for the reply and for cuing us into Formlabs’ research into alternative solvents, @tech_nickl. Very helpful!
What does “not compatible with the Form Wash” mean in the specific context of Yellow Magic 7?
On the topic of TPM/DPM, can anyone comment how the washing action of these work compared to IPA (creates a solution of resin dissolved in IPA) or Yellow Magic 7 (simply washes the resin off the part)?
Is it possible to capture the resin out of the TPM or DPM after it has been used for a while like Yellow Magic 7?
Has anyone used a particulate filter to try and filter out the IPA bath in a Form Wash? It seems some of the Form Wash problems could be solved if there was a pump & filter running while agitating to keep the contamination down…
I won’t speak for Nick here, but typically that kind of incompatibility points to some aspect of the solvent not playing nicely with some material inside the machine over a longer period of time, increasing the chance of issues with the Wash.
Alternatively, it could be that the solvent doesn’t last for enough washes, or affects the actual printed part adversely etc etc.
I contacted DOW for distributors of TPM in my area and they denied to do business with me since I am not a registered business owner. Is TPM only available to business exclusively?
I have tried reaching out to DOW as well. They refused to discuss selling the material since I am a home based business. It did not matter that I have a business license and LLC. I have yet to find a distributor. Maybe I just do not know how to look up the correct distributors on the internet. I am located in Birmingham, Al.
For TPM we use 15 minutes for most materials. Glad to hear DPM is working for you. We just can’t recommend it due to the damage it causes to the Form Wash. It is compatible with our resins though.
As mentioned above, DPM and Yellow Magic will eat the powder coating, but it may have other effects as well, especially when mixed with resins. Basically use at your own risk in the Form Wash.
To your other question, TPM, DPM, and IPA are solvents. They actually dissolve the components of the resin into solution. Yellow Magic 7 seems to mostly act as a detergent and keep removed resin from re-depositing on the part. That’s why it works well with ultrasonic cleaners.
Mechanical filtration of the solvents won’t remove the dissolved components, but it may remove pigments and other large particles that could extend the life of your solvent somewhat.