Casting Catastrophes

Finally, a post that has long been neglected… the results of my casting adventures.

The short version is that although I did not achieve my original goal, my casting experiences did lead me to some useful things that have simplified some of my creating.

And here’s the long version:

Man, casting is hard. Huge props to those folks out there who do this regularly with lovely results. I’ve wanted to learn how to make molds and resin casts for a long time, but I haven’t been brave enough to try. That, coupled with the start-up costs and the fact that I didn’t really have anything worth casting held me back. But with a passable rider finally sculpted and my wish for many more, I decided to dive in.

The first thing I did was do some research online. I particularly recommend watching this video and reading over this page. I learned that this shape would need a two part mold, as opposed to a one part mold for things with flat backs (like medallions, for example). The video above was extremely helpful is explaining how a two part mold works and what to expect.

I found that making the mold itself was relatively straightforward.

mold p2 - finished mold

The first of several rubber molds

Pouring the liquid resin was a lot harder. I had a lot of trouble getting it to fill in the mold, and/or overflowing out the sides. I have a feeling that despite the seemingly easy creation of the molds, they had some serious flaws that prevented them from working properly. I made several molds trying different ideas, but none of them worked 100%, and some results were rather scary.

Some early attempts, from a few different rubber molds.

Some early attempts, from a few different rubber molds.

After a lot of frustration, I more or less gave up. But I did do one last mold. I realized that most of the difficult details to sculpt- hands, leg position, face, and helmet- were all on the front of the rider, that I could do a one-piece mold and at least get some usual pieces out of it.

The finished one piece mold, with my original still embedded

The finished one piece mold, with my original still embedded

And that worked, as well as it could anyway. It was much easier to pour the liquid resin into the one-piece mold, and also to get it to fill the whole mold. And the results, although incomplete, have turned out to be very useful.

The results of the half cast. Here I'm starting to build the back half of the figure, starting with a foil fill.

The results of the half cast. Here I’m starting to build the back half of the figure, starting with a foil fill.

So now I can at least dependably get half-riders out of my mold. They don’t all come out with hands, but I’m developing a decently fast way of sculpting them. And having the face, helmet, and basic body shape established in the casting is a huge advantage for sculpting. Each rider still takes a decent amount of work, but WAY less than sculpting each one from scratch.

5 responses to “Casting Catastrophes

  1. Have you thought about making a cast for the back, like you did the front, and then epoxying the two together?

  2. Ooooh, looking good!
    Have you thought about making a one piece mould in silicone? You’d need to cut it open to remove each casting and then tape it up again for the next but when I’ve cast oddly shaped things at college it seems to work out quite well.

    • Sounds interesting! Is that like the stuff that you paint over the thing you want to cast and then it hardens? Also, when you tape it together does it still cast decently? I would think the resin would leak out the holes… teach me your ways, master prop-maker :D

  3. Kind of, but for small things you can just pour it over the whole piece in a cup or other mould and because it’s flexible silicone it means you can pull the mould apart far easier than if you had it in another material.

    http://www.smooth-on.com/gallery.php?galleryid=289

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