Thursday, September 21, 2017

Getting primer to stick to resin: a primer on mold release agents

In hunting around, I found a number of companies that offer mold release agents. I also found a model hobbyist who makes resins and posted on release agents here. (Let me know if the link stops working, I have saved the file).

This fellow uses a commercial agent called Mann Ease Release 200 (spray) or 205 (liquid). He also makes his own, made up of petroleum jelly thinned with mineral spirits which he then applies with an airbrush ...  anyway the MSDS (here) states it includes dimethyl ether and 1,1-difluoroethane. I figured the fluorine component is likely the part that makes it nice and slippery, but an actual chemist informs me that this is the propellant, and that the actual release agent is not listed.

Mann also lists Mold Cleaner 2508 for removing traces of prior mold release agents. The MSDS for a competing product (here) lists xylene, toluene and our old friend, MEK (methyl ethyl ketone). So whatever the release agent might be (Vaseline?), these are likely the solvents needed.

The next question is what is the impact of MEK on resin parts. Trials with a scrap piece may be in order. As I don't have any MEK on hand, I will report back.

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