Flexible Foam and Creatures in the Third Dimension

One thing I always wanted to do with the creature drawings was to try and bring them from their flat, 2-D world into our fully realized 3-D one. Naturally, not every creature lends itself to 3-D, but some would make for quite interesting models.

While I was still in school I was taking a class on flexible molds; mainly dealing with rubber, silicone, and things of that nature. I figured it was the perfect chance to try and make some casts of one of the kids creatures, so I went about doing it!


The creature I chose was the funny little orange guy from one of the groups ‘desert’ creatures. He had a nice thick shape and wouldn’t fall over if I tried to translate him into the third dimension, and besides, he was funny! Here you can see the finished product, made from orange dyed flexible foam (almost like a Nerf material), with some eyes and a mouth that I drew on myself.

But how did I get to that point?

At first, I made a model of the creature from plasticina. The oil based clay doesn’t dry out in air, and generally wont stick to anything in the mold either, so it’s perfect for this kind of thing. From there I had to find a “parting line” for the mold, which is usually down the center of an object, as it is here (roughly). Then, I had to pick a place to pour my casting material into, one which wouldn’t be very obvious on the final piece. In this case, there’s a small spout under his belly. After all of that I painted on various layers of rubber, building up the shape you can see here, which ultimately becomes the rubber mold you would cast into.

Once all of that dries, you need a 2nd mold out of a harder material to carry the softer mold inside and keep it from moving while the cast dries. For this we use plaster jacket that goes around the rubber. You can see the large shell I built up along the seam, with little locking keys so the pieces fit snugly into one another, and holes drilled through to bolt the entire mold together tightly right before you pour something in.

After the plaster dried, I had to pry it apart, open the rubber mold, and finally take the plasticina prototype out of it. Put all the pieces back together and you end up with this again, with the hole in the center there ready to pour. Remember at this point the creature is upside-down, and the pour spout will be on his underbelly. Due to gravity and air pressure you have to be careful not to have parts of the mold be above the pourspout, or they’ll never fill due to air blockage. You can make tiny airholes at these points so that air can escape and the casting material can fill them in, but theres still a chance it may settle lower into the mold than it’s supposed to. I had this problem slightly with the creatures stubby feet.

Anyhow, I cast using the flexible foam, which you mix and then have to immediately pour into the mold as it expands many times its original size. So a very small drop of foam will fill a huge area of the mold. I placed a brick over the pour spout to try and contain the foam and ensure it filled all the cavities, but as you can tell from the mold itself, some of it exploded out through any crack or crevasse it could squeeze itself through! After all is said and done, you simple unbolt the plaster jacket, pry open the rubber mold, and pop out you casting! What could be easier, right?

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