Tamiya thinner causing parts to shatter?

Hiryu02 · Post by **Hiryu02** » Thu Jan 24, 2008 12:24 pm

Please forgive me if this is a breach of etiquette, but I thought the painters here might need to hear of this.

A fellow over at another forum claims that Tamiya thinner caused his parts to become brittle and shatter when used as a thinning agent in a wash.

The thread can be found here:
http://www.mechatalk.net/viewtopic.php?t=8701

you might want to hop over there and see how this develops, as I've never heard of this product behaving this way.

Just a heads up.

Kylwell · Post by **Kylwell** » Thu Jan 24, 2008 12:43 pm

More than likely it was the hardware store spray bomb that did it, if anything. Or, he just got a one with crappy plastic.

Hiryu02 · Post by **Hiryu02** » Sat Jan 26, 2008 12:46 pm

Well, there might be some merit to this after all. I just recieved a new Bandai kit, and there is one runner that is marked ABS. This runner/sprue is mainly for the joints as far as I can tell. I guess Bandai is changing joint connections from polycaps to ABS plastic on some kits.

I looked up ABS plastic on wikipedia and among the characterics listed is the fact that it will dissolve/degrade when exposed to acetone. Which I belive is an ingredient in Tamiya thinner, judging from the smell.

I will test this myself soon on a scrap ABS piece, but in the meantime this guy's claim may hold some water.

Kylwell · Post by **Kylwell** » Sat Jan 26, 2008 1:57 pm

Acetone? Tamiya acrylic thinner is isopropyl alcohol and contains little or no acetone. Acrylic paints may contain acetone derivatives but so little as to be negligible. It's a solvent, it's supposed to soften plastics.

ABS, on the other hand, can be prone to bouts of brittleness and are especially susceptible to acetone (where they tend to dissolve).

My guess, as last time, Bandai is just making the stuff too brittle.

Or he's playing with the model too much and breaking it.

It happens.

Hiryu02 · Post by **Hiryu02** » Sat Jan 26, 2008 2:11 pm

Ah, my mistake on the acetone. In any case, I'll test it myself soon and post the results.

I certainly hope that if Bandai is making the stuff too brittle, that they pick up on it soon and rectify it. I just feel bad for this guy who basically just deepsixed his 2.0 Zaku. I'd be severely distraught myself.

Kylwell · Post by **Kylwell** » Sat Jan 26, 2008 2:22 pm

So would I. I'm thinking about cracking my Gelgogg 2.0 and test the ABS in it to see if I can get a reaction.

Really wish Tamiya would hop on the MSDS bandwagon.

Hiryu02 · Post by **Hiryu02** » Sun Feb 03, 2008 10:17 pm

Well, I did a small test, I immersed a small flat scrap ABS piece in Tamiya thinner. Let it sit for a few minutes then removed and dried it. It did SEEM to bend more easily.

It's hardly conclusive, I'll try another test with 2 similar pieces next, and keep one dry as a control sample. I'll post if the results are conclusive.

Kylwell · Post by **Kylwell** » Sun Feb 03, 2008 10:24 pm

I've had a piece of ABS sprue in thinner for about 4 days now. Pressure tests for bending seem to be equal.

DasPhule · Post by **DasPhule** » Tue Feb 05, 2008 4:53 am

I've found that using Naptha as a wash thinner will make all brands of plastic shatter if it sits on it too long. Bandai kits are especially prone to this cracking, and not just from naptha as I've seen the Tamiya spray cans do it as well. Their sprays are about the hottest paints out there, they'll melt plastic if put on too thick.

Apparently, Bandai's styrene is sensitive.I've never had their ABS melt or shatter, and I've sprayed it with everything, including Alclad II's (hot). Best bet is to clear coat liberally with Future, I've only experienced the shattering when I didn't use Future to block the naptha. Future blocks pretty much everything that isn't ammonia once it's dry and set. Maybe this would help with the Tamiya problem?

Erin
<*>