Testing IPA, Yellow Magic and RTX with castable resin

Continuing the discussion from Replacing Isopropyl Alcohol with Yellow Magic:

Hi All,
As part of our ongoing quest to find a replacement for isopropyl alcohol during post-print clean-up, I ran a test comparing its use against two products from Bradley Systems: Yellow Magic-7 and RTX-9.

Free samples are graciously provided by the team at Bradley Systems to any FormLabs Support Forum user who requests it:

Christopher Targosz

Results: In short, neither product completely eliminated the need for at least a short IPA bath. However both products did a very good job replacing IPA in the First Stage cleaning process. Yellow Magic has the added benefit of being more resuable than either IPA or RTX.

This test focused on the use of castable resin, since it requires an extended UV cure step. Our hope was the UV cure would help to remove the ‘tackiness’ left behind by YM and RTX and make IPA unnecessary.

Freshly printed parts were submerged in each solution and agitated. Both YM and RTX are water-based, so are able to be used safely in an ultrasonic cleaner.

Since they are less volatile than IPA, it’s easy to add a quick scrub with a chip brush to the process with YM and RTX.

All pieces were dried with compressed after the First Stage cleaning. A quick IPA bath was given to one print-out from each cleaner for later comparison to “cleaner only” parts.

The prints were then exposed to a UV cure for an extended period of time.

The best results continue to be parts put through a double IPA bath, but a Yellow Magic initial bath followed by a quick IPA rinse is nearly indistinguishable.

The YM and RTX “cleaner only” baths created parts that failed to fully cure, remaining somewhat ‘tacky’ even after the extended UV cure. Neither product alone produced parts ready for investment casting.

Yellow Magic continues to have the added benefit of reusability. A quick exposure to sunlight or a UV curing box solidifies the captured resin, allowing the solution to be reused. The RTX is a more aggressive cleaner, and is mixed with water-- perhaps the reason why it congealed when exposed to UV.

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Great comparison. YM is probably much better in the first stage since you don’t end up with a sludge similar to the first bath of IPA. On an environmental side it makes more sense.

I’ll see if the clear cures up better without IPA, I’ll be at the mercy of the gods and wait for some sunshine.

I think a test with clear resin is a good idea, Ken. Fingers crossed for sunshine. :smile:
All the tests I ran with RTX used a diluted solution. Do you think a full strength test is worth the effort? (I did leave one of my tests in RTX for three days-- still tacky.)

-JD Davison
The Lab Partners

I did some initial test with straight concentrates of YM, RTX and Clean and Safe
YM and Clean and safe performed similar. YM a little better. RTX as a concentrate worked no better than diluted 1:3 water so I think it would be just a waste of material.

If you want to get rid of stickiness just put the prints in water while curing them!
I had amazing results with that procedure!
I just print the stuff, put it in IPA for 2 minutes, put it in a container filled with normal tap water and put it ouside (even on overcast days there is enough UV-light to nicely cure the prints within an hour).

Since I started doing this I never had any problems with sticky prints anymore!

Why in water? Because Oxygen seems to prevent the resin from activating (hardening) and thus the prints stay sticky independently of how much UV-Light we shine on the stuff! Under water, the oxygen is locked out (the oxygen content of the water does not seem to matter) and enough blue / UV-Light passes to harden the parts reliably.

Still, replaxing IPA seems a good idea!

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Maybe someone can tell me why the test of items other than IPA? At first I had a difficult time finding it at the 95%+ but that is not a problem now.



My motivation for testing out other methods of cleaning parts is to eliminate the need to have flammable IPA in my home.

IF I can find a product with the correct procedure that eliminates IPA, I will be very happy.


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Thanks - I get it now. The IPA is nothing. I have various cans of auto lacquer thinners and 100s of bottles of train paints in my shop. Plus the oxygen and acetylene B tanks too. All for making the fire “interesting”.


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My main purpose for replacing IPA was because the types of parts I print tend to warp and the brittleness of the parts made it difficult to get a mold out of them without shattering…

I’ll try uv curing in water.


Hi All,
Just to add to this alternate rinse agent topic, I used the M7 in combination with tap water and sunlight. What resulted is great results on a black resin part run.
I left the supports on and submerged 4 identical parts into a clear plastic food container that was filled with just YM7 for about 15 minutes and in direct sunlight. I then moved those black resin parts into an open topped plastic measuring pitcher with just tap water , also exposed to sunlight for about 15 minutes. I removed the parts and set them onto cardboard to let dry. They were exceptionally clean. I think, at least for black resin, this is going to be a much better cleaning experience.
Now, I should probably tell the guy who kindly sent me a sample that so far YM7, tap water and sunshine are a good cleaning solution for the black resin. Have a good night!

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Can you please post a link to that YM7 thing?

Here ya go, Silvio.
Free samples are graciously provided by the team at Bradley Systems to any FormLabs Support Forum user who requests it:

Contact:Christopher Targosz

Fantastic suggestion, Temujin.

I’ve been using Yellow Magic to clean my parts, followed by UV cure-- I never thought about combining the YM with the UV cure.

That’s today’s test. :smile: Bravo.

-JD Davison
The Lab Partners

Thank you both, I will give it a try. Would like to avoid having such a inflammable thing laying around in the office.

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Just a quick confirmation (pictures to follow later):
@TemujinKuechle is correct-- leaving the parts submerged in Yellow Magic during a UV cure removes all tackiness.

My experiment used Castable resin-- which usually takes quite a bit of UV time. After a relatively short cure there is no tackiness at all.

-JD Davison
The Lab Partners

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