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Molding small sculptures: EasyMold vs ComposiMold vs Smooth-On Silicone Rubber

I’ve talked a lot about sculpture – and most of the work I’ve done has been more along the lines of constructing sculptural pieces. Found objects, old treasures, vintage electronics all coming together to for an sculptural object. Robots! Desk sculpture! etc. This winter I took up casting epoxy jewelry, which was fun. I was looking for some way to make Glow-in-the-dark jewelry. Which was also fun! Fun all around, but I quickly realized I wanted to make some molds. Or at least make molds and then cast some unusual jewelry parts.

That meant finding a good mold making material. I bought some EasyMold Silicone Putty. Not bad – very easy to use – quick. Unfortunately I noticed it often had gaps – likely the way I used it. The putty would also sometimes get pressed too hard (causing the items to slide around? and become out of shape) – or pressed around the item too lightly – and not pick up detail in the gears. EasyMold review: 6/10 – not bad but not right for me.

Next up: a reuseable mold making material: ComposiMold. Wow, this stuff seemed perfect. I imagined so many ways to build and reuse a mold. My head exploded. It came (alas) with almost no instructions. It should have come with a BIG note say: heat this slowly or you will get bubbles. Many bubbles. And you won’t be able to get them out. I never ended up casting anything because I could never really get it clear enough. I made 3 or 4 molds, but looking at the surface I could see little bubbles on the surfaces. This would not create good edges etc. All I could imagine was creating something that would have so many microbubbles that I would immediately toss out the items. It is probably GREAT for … small casts of something. Candy! Chocolate… I dunno. Something not what I am doing. But – they are awesome at answering Facebook questions. Very nice. Quite helpful. Too bad I’d used 70% of the material to create a bubble-filled pile of composimold. One day I might try that 30% that I’d not heated yet. I’ll microwave it VERY SLOWLY. soooo slow. maybe that will help.
ComposiMold review: 4/10

Smooth-On Silicone Rubber:
I went to a sculpture supply store in Etobicoke. It was around the corner from a factory I worked at in 1980s. I went with my Dad who knows everything about almost everything, including molds and casting. On the first trip I picked up material that would need to be vacuumed… and gee. Did not yet use it… because Degassing is a Pain in the arse. Very importantly though, I bought some modeling clay – which has changed my life. More on that later.

On trip #2 I talked to the staff who suggested Smooth-On Silicone Rubber – easy to mix (1 to 1 ratio), no degassing needed (aka vacuuming), pour and quick demold (6hrs).

Smooth-on was exactly what I needed. EXACTLY. It makes great molds, good detail, doesn’t seem to be full of bubbles and keeps great texture. There’s a bunch of YouTube vids about using it… and they are pretty accurate. I would only suggest: if you can use it outdoors, or in a super vented area – do so. Wear proper gloves. Pour slowly.

smooth-on Silicone Rubber review: 8.5/10 (possibly higher but I’ve not tried everything yet!)/