Friday, July 3, 2015

09 Plaster Production Molds Nº 228

I started to place the coddles around the mold, for pouring the next mold piece. Click on any image to enlarge it.

I fastened the two side coddle boards opposite each other.

Then I sealed the spaces between the coddles and the oil clay build-up.

I put the back coddle board in place, secured it with clamps, and sealed around the bottom with oil clay coils pressed into place. I still need to apply parting agent to the plaster in front before I mix and pour the plaster.

How much water and plaster will I need? I did a little bit of arithmetic to get a better estimate.

Referring to the rough sketch above, which is not to scale, I took some measurements of the area I will be pouring next. The build-up has a slight angle, so when I measured, I took that into account. First I figured out how much volume the wedge had. Then I figured out how much volume the block had. I added the two volumes together. Then I took two thirds of the total volume as the amount of water I will need. I subtracted a cup of water for the lower torso that is sticking into the area. That isn't exact, it is a conservative estimate. Anyway, I got 11.89 cups of water, which I rounded up to 12 cups of water. 12 cups of water weighs 96 ounces, which is 6 pounds. The ratio of water to plaster that I want is 2 parts of water to 3 parts of plaster, by weight. So I will measure 6 pounds of water and 9 pounds of plaster for this mold part. The plaster costs about 47 cents per pound, so I will be using about $4.23 worth of plaster for this mold part.

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