• Robert Buehler

Digital Fabrication: "Fitting the Mold"

  1. I began the project by copying the bird form from my previous "unwrapping project". Ising the bend tool, I angled the head upward, bent the tail back, and added volume to the chest. I did this to accomplish a more "perched" look for the bird.

  2. Using the cone tool, I created a beak and conical base for the bird figurine. I connected these forms with the Boolean Addition tool.

  3. Once the form was satisfactory, and resembled a figurine one might find on their grandmother's mantle, I centered it within a hollow box form and split it in half. These halves would be the foam molds which plaster would be poured into.

  4. With the forms flat on the X plane, I was able to transfer the file from Rhino, and CNC the mold from 2" Pink Foam.

  5. When my mother molds were completed on the CNC, I sanded the surfaces to reduce the foam catches. Then, I brushed on joint compound and sanded this (when dry) as well to achieve a smooth surface on the bird positives.

  6. With my foam mother molds prepped, I was able to pour the plaster which would create the negative halves that slip would be poured into. (I didn't photograph in the plaster room because I had gloves on and I didn't want to drop my phone in any powders or liquids)

  7. Once the plaster molds were solidified, I sanded down the edges so they could be easily strapped, and no plaster would chip off into the slip.

  8. When slip casting, you have to "season the mold" before you can get a proper cast. Generally, this takes one or two pours of slip into the molds. I made two separate plaster molds so I had to do four total trial pours before the molds began to function. by the end of the day I produced seven small birds that I was pleased with.

  9. Once the casts were dried a fair amount, I was able to knife off the majority of the seam. I waited until they were nearly bone dry to sand the seam completely.

  10. With the seams sanded, I was able to fire my seven birds - five with bases and two without. Unfortunately, because I fired straight to Cone-7, the tails drooped a bit (but I suppose it adds a bit of character).

  11. When the birds were removed from the kiln, I did some sanding on the bases with a diamond disc bit for my Dremel, and applied a black gesso while the figurines were still warm so the acrylic binder would absorb well and dry quickly.

  12. Once the gesso was dry, I used oil paints to differentiate two males and one female.

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