Tuesday, October 13, 2009

Pouring the mold pt 1

Jesus crucifying fun!
Okay, it's time to make one half of the mold. First thing we need is hydrocal, our molding material for this project. I got my hydrocal at Blick, they have it at art stores everywhere.
The hydrocal comes as a powder and you have to mix it with water. There are measurements and ratios to judge how much water to hydrocal, but no one in the world uses them. Before you mix, make sure to draw a pour line on the inside of the wall. This should be about 1/2 to a full inch above your highest point on the sculpt.

Mixing hydrocal is just like mixing plaster.
To mix the hydrocal I needed a plastic mixing bin. I needed to make a quick judgement of how much molding material you'll need. Pour half that amount IN WATER in the bucket. It's very important to pour the water first. Also, I made sure that there was more than enough room left in my mix bucket for the hydrocal.
I started by quickly sprinkling the powder into the bucket, by using a small paper cup. *Once you start putting in the hydrocal powder into the bucket, do not move, mix or shake the bucket* I kept doing this, evenly, until the powder stopped sinking to the bottom. I look for what has been described to me as the "dry cracking desert" look.
Yeah, that, only with hydrocal. Once this happens you will start to mix, which is done with your hand, so that you can feel lumps and mix them in better. Before you start mixing, make sure you have everything ready to pour, you don't want it to set up on you before you're ready to pour. So, you're ready. Roll up your sleeve and mix. This stuff doesn't have a lot of working time, so mix quickly. Once thoroughly mixed, you can begin to pour.

Pouring is a scary and dangerous. This is because of air bubbles. You need to make sure you don't get any air bubbles on the sculpt surface because it will result in a "zit" in the final cast. There are a few different pouring techniques to avoid air bubbles; I used a combination of them. One is to paint on a first layer, so you get all the intricate details. I did this on a few areas, like the arm pits, shoes and hands, that I was a afraid of getting air bubbles on. I did this very quickly. Then I started pouring at a medium and steady speed in a corner far away from the sculpt. I let the hydrocal move into the cracks and crevices. Once one part is pretty full, I moved to the other side.
Once I poured it there was nothing I could do but wait. It says that it sets fully in an hour, but I'm extra paranoid and I left it sit for about 5 hours. The hydrocal sets in about 20 minutes and gets really warm, I've been told this is the best time to demold. MOTL

Mold is poured!

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