Casting Your Own Parts: Part Two, Reconstructing Joe


The last time we saw Joe Turtle , he had been disassembled, trimmed, and reassembled him. We left off as Joe was getting his first coat of latex molding compound applied to his little self. Mmmmm….mold compound (not for eating folks). After 11 coats, we find Joe snug in a little latex cocoon, waiting to be released. Now it’s time to see how things turned out and try out some plaster casting.

It took about a week to get Joe to this stage. You can only lay down a coat or two of the compound a day. Typically you use a brush. The compound needs to cure completely between coats or you will have pockets of latex that will take forever to cure (like weeks). That’s a draw back to this technique. Of course, the advantages to the technique are that it’s easy, not prone to air bubbles (bad thing), and it’s inexpensive. You can find latex mold compound (sometimes called mold builder) at craft stores or online. A pint will put you out less than $10 and make a dozen or so molds. This material also works best if you keep the subject you are molding down to less than 2 inches. The more coats you use, the better the results as well. I’m pushing it molding something as large as Joe and only going to 11 coats - 20 coats would be better.

After the latex cured up, I popped Joe right out of his latex shell. Doing this takes a minute or so. Moving too fast pulling the latex off will rip the mold. The patience pays off though; the detail replicated by the latex is outstanding!

The white pedestal the subject (Joe) appears to be sitting on is modeling clay. I did this so the latex would not “wrap around” the subject. This mold is a one piece open face type (sometimes called flat backed). Latex isn’t flexible enough to wrap all the way around the subject. Not a problem if you are looking for something that will be mounted to a case.

Of course, once you have a mold, there is only one thing left to do. Cast with it!

For casting – especially for fun casting, plaster of Paris is our friend. This stuff is pretty safe to work with (no fumes!), washes out of clothes, takes paint well, and costs only a few bucks. It’s been used to cast just about everything, including tire tracks for crime scene shows, the occasional Bigfoot print for those Leonard Nimoy narrated documentaries we all so love, and belly buttons. Best of all, it sets up in about 20 minutes. Compare that to epoxy which can cost many times more, is messy, toxic, and takes 24 hours minimum to cure, and you can see the benefits. The only down shot would be that plaster is a bit soft – about the harness of soapstone.

I mixed up a plaster batch, poured it into my mold, and gave it half an hour. Voila….Son of Joe is born!

The mold and plaster record pretty good detail. This whole project from start to finsh ran about $20 dollars with enough left over material to make more molds and many more casts. There is a bit of distortion on the shell I could have avoided with a thicker application of latex (I was pushing the technique a bit). The finished product is also a bit thick but, because plaster is soft, I can carefully sand down the base until I have it just right. And if I break it? No big deal. A good latex mold will give you about 50 good castings in plaster. I can make a whole army of Joes 20 minutes at a time! Of course, that brings me to an obligatory note about copyright.

The original Joe was made by Safari Ltd . These guys put a lot of effort into their craft. I would never violate a copyright by casting off pieces of their (or anyone’s) work and trying to sell or distributing them. For a one-off or for fun it’s fine to use a toy model, but to make pieces for distribution requires using an original or natural subject. Fossils work pretty well as an example.

Where do I go from here? Well, we’ll just have to see, but I do smell epoxy resin casting near by – calling me, taunting me, making me forget about dinner.

‘till then, Happy Modding.

Your bit of bling comes from WilletFX again . It’s an oldy, but shows Willet mixing latex - as a casting material. Short, but informative.

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