Attempting casting resin in two colors, part three- success!!!

 Check it out! Jawsets cast in two different colors! Aren't they bee-oootyful??

I decided to try a method I had thought about before but had dismissed as too difficult- making separate models of gums and teeth, making sure they fit well together beforehand, and then molding them. I knew that teeth and gum components carefully cut apart from a single a rubber jawset model and molded separately would make casts that would fit back together with no problem. However, as I wrote about in a previous blog post, the repeated  molding and casting in rubber that this method requires caused  bubbles to build up in the casts over time. Yuck!!

So I would use teeth I cut out of a resin cast to make that part of the mold. I would use a plasticine  "borrowed casting" of the gums (I talk more about this technique in this blog post), physically removing any bubbles before molding it. Bubbles can be removed from plasticine but not from rubber!  I would make sure the teeth and the gums fit very well together before making molds of either. The big challenge would be not squishing the models and ruining the fit during this process.

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Which brings us to this picture. Why, you may reasonably ask, is there a jawset model in my freezer? Very simply, freezing the clay helps keep squishing to a minimum, so I can check the teeth and gums for fit and do as little damage as possible. This kind of plasticine, Monster Clay, contains a high amount of wax, so it freezes very well. 






Pictured here are another secret weapon in my arsenal, rubber tipped shaping tools. These also helped keep squishing to a minimum, as they made it possible to apply just the tiniest, most precise amount of pressure to only the areas it was needed. Unlike big fat fingers.


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Above, the plasticine gum models in their Lego mold boxes, ready for rubber.

Right, rubber poured over the models. Coloring it like this helps to show when the two parts of the rubber are fully mixed, so that it can be stirred only as much as necessary, avoiding excess bubbles. Pouring the rubber into the molds from relatively high up, in a thin, slow stream, also helps to break bubbles that have formed while stirring. Brushing a thin coat of rubber over the model, letting it partly set, and then pouring the rest of the rubber in also helps, as bubbles trapped against the model can more easily rise to the surface and break that way.

And, resin gums poured into the two new molds.

 

​Teeth waiting for rubber in their own Lego mold box...

​And rubber poured. Another thing that helps eliminate bubbles is tapping the mold box on the work table after the rubber is poured, to help the bubbles rise up to the surface and break.









 (I found myself often thinking of this scene from Finding Nemo during this whole thing...)

​Resin gums cast into one mold, teeth into the other...

​And, teeth and gums removed from the molds, and... THEY FIT TOGETHER!!! YAAAAAYYYYY!!!!

I said it before, and I'll say it again... aren't they bee-ootyful???!!!