Props, Scenery, Costumes and Makeup: Epoxy/latex release agent?

Epoxy/latex release agent?

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Topic: Epoxy/latex release agent?

Posted By: Kurt_Muller
Subject: Epoxy/latex release agent?
Date Posted: 10/07/07 at 11:19pm

I've made a latex mold of my Hathor cow horns for Joseph, and I want to pour epoxy resin into it, to make four horns.

What the best release agent for that? And do I have to recoat the inside of the mold each time I pour resin?

Thanks.

Kurt

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"It's only a mooovie".

Alfred Hitchcock

Replies:

Posted By: TonyDi
Date Posted: 10/08/07 at 9:40am

Well first of all any time you plan on doing castings in epoxy resin the better choice is always going to be silicone mold materials. HOWEVER, the biggest issue in using any of the rubber products including latex - which is the weakest by far for casting resins that heat up to cure - is the degradation of the mold material - in this case the latex mold. BUT if you need just a couple castings you'll likely be ok. It may last longer than that but even silicone molds are limited life with high temp cure resins.

Nevertheless you can try any silicone based release agent. That's the norm - they're spray on and easy to apply because of that. You can try any of the following:

From the MANN company Ease Release 200 - silicone based release agent

From Silpak MS122 which is a TEFLON release agent but suitable for epoxy resins

From Cil Chemical - you can try CILRelease 1711 E - which is also a silicone based release agent.

There are likely dozens of other release agents you can use - it's just a matter of seeking them out. For instance FREKOTE #1711 MOLD RELEASE is a standard one for epoxy resin release, You CAN often get away with using DC 200 silicone fluid sprayed on with a Preval unit sprayer. That sometimes will work. TALC might even work as well in a latex mold. But here again latex is simply the low end choice for mold making and should be used only when it's not a crucial part which requires many castings. But if you're hitting just a couple castings you should be fine with it. Even Vaseline MIGHT work - as long as it wouldn't inhibit the cure of the resin BUT it's death to latex for sure. ANY petroleum product will deteriorate latex quickly but for a quick one-off it might work in a pinch - though I DO NOT recommend it.

Good luck

TonyDi

BTW you should LIGHTLY respray the release in each time you cast. The heat produced by the epoxy resin will sufficiently reduce the release properties that you should likely do a light re-coating with the release agent. But in a single spray can you should have PLENTY to do that with...just to be on the safe side.

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"Almost famous"

Posted By: Kurt_Muller
Date Posted: 10/08/07 at 7:07pm

Thanks for that, Tony.

I'm using latex as a cheap option. I know silicone is better, but getting it involves a long trip for me. I'm casting four curved cow's horns for "Dreamcoat". I'm not too worried about the third or fourth casting turning out rough, because I expect to have to do some sanding afterwards anyway.

Glad you mentioned about Vaseline. I had planned on using it until I read that!!

Thanks again.

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"It's only a mooovie".

Alfred Hitchcock