Friday, March 21, 2014
09 Plaster Production Molds Nº 4
Coddles are used to surround the model that is being cast, in order to contain the poured plaster. I have always made my own coddles. Basically, coddles are made from four pieces of wood that are a sufficient length and height, with small blocks attached to one end of each piece of wood, for clamping the coddle together securely. I usually seal the coddles with three coats of orange shellac. Click on any image to enlarge it.
The length of the coddle boards should allow for the longest pattern plus at least 1.5 inches on each end, and the width of a coddle board and block. For example, the longest pattern on my doll is the lower leg, which is 7.5 inches long. If I make the block from 2x2 stock (1.5"x1.5"), and make the coddle boards from 1x stock (0.75"), then that will be 2.25 inches. So 1.5" plus 7.5" plus 1.5" plus 2.25" equals 12.50 inches. I always add a little bit more to the length, so the minimum length I would make my coddle boards would be 12.75 inches long. I will probably make each one of them about 14 inches long instead of making them the absolute minimum length.
The height of the coddle boards should be high enough to allow for a mold to be made of the thickest pattern, plus 1.5 inches above and below it. Chaney & Skee suggest making the clay build-up that goes around the pattern to be 2 inches wide, but I have always made it 1.5 inches. The thickest doll pattern I have is the lower torso, which is about 5 inches. So 1.5" plus 5" plus 1.5" equals eight inches. I will be making each coddle board 1x8x14 inches. The 1x is actually 0.75". Each clamping block will be made from an eight inch length of 2x2 which is actually 1.5"x1.5".
Even though I have not mentioned it yet, note the molding board with the cleats on the bottom, in the last diagram. The cleats allow for everything that is built on the molding board, to be picked up easily.
Martha Armstrong-Hand describes her coddles which were made from 3/16" thick aluminum plate. The clamp ends were made from pieces of aluminum angle. The angles and plates were fastened together with machine screws. These would be the Cadillacs of coddles.
Chaney & Skee mention using rolls of linoleum as coddles. The linoleum is wrapped around the pattern one and one-half times, secured with clothes pins, then tied with cord and the bottom edge sealed with clay.
I have also heard about people using Lego bricks to make coddles. Since I am not of the Lego generation, I do not have any Legos, and they are much too expensive for me to purchase them for use as coddles when wood is so inexpensive and easy to cut and assemble. But if you have them, you may want to try them.
If the coddle material is porous, seal it before using it. To maintain the same consistency between all mold parts, the coddles should not absorb any water from the plaster mix after it is poured.
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