Wednesday, September 19, 2012

06 Waste Molds Nº 10

I finally decided to go ahead and use the one-piece block moulage mold coddle with the oil-clay arms inside. I opened my new 5 pound bucket of moulage and put it in the stainless steel stock pot in the double boiler. When it is brand new, it looks like it was chopped up by a food processor. The pieces are really small. When this batch melted, I added the other 6 pounds of moulage that I had chopped up and stored in jars, after my last mold making event. I add some moulage, stir it up, let it warm up, then add some more, and so forth, until it was all in the pot, and melting. Click on any image to enlarge it.

This coddle is about 13 inches tall, so I used the mold vibrator when I was pouring the melted moulage into the coddle. The vibrator helps the moulage to settle around the model evenly. I also use it when I am pouring plaster molds. It is a very nice tool to have. Mine is made from a used eletric motor found at a yard sale. Here is more information about the Mold Making Vibrator.

Finally, the moulage was ready to pour. I dumped it from the stainless steel pot into the moulage bucket, then poured it into the mold. It took two pours, with the vibrator running. I used almost all of the moulage. I am glad I melted all that I had. The coddle started to lift up slightly in a couple of places around the base, so I weighted it down and left it to set up. I am very glad that I used the pieces of wood around the coddle. They worked out really good.

This is typically how I make my molds. No two molds are exactly alike. Every mold making event is an exercise in problem solving. Because of all the wood, I cannot cover the moulage with a plastic bag while it is setting up, so what I did was to pour a little bit of water on top of it. I will keep an eye on it until the mold is completely cool. Then I can remove the pieces of wood, and the cardboard coddle, and cut the mold open to remove the oil-clay, in preparation for pouring the carving wax.

While waiting for the moulage to cool and set up, I found this information about Alginate and Moulage from Thurston James' The Prop Builder's Molding & Casting Handbook. His book has all kinds of information about esoteric molding and casting materials. As the section on Alginate explains, it is perfect for making molds from life. Alginate is a use-once molding material. It does not have a long shelf life, and it is not reusable. Because it is mixed with cold, or room temperature water, it cannot cause any burns. Hot-melt moulage is also alginate based, and shares some of the properties of Aliginate, which is why I included it here, with the Moulage information. There are some differences between these two mold materials. Moulage is reusable, Alginate is not. Alginate is mixed and used cold, Moulage is melted to make a mold. Both materials will shrink a lot if left to dry. So always cut the Moulage up and store it in a container with a tight-fitting lid after using it. Click on any image to enlarge it.


I pulled the mold too soon. It was still not setup deep inside. Also, I had attached the spare really good to the molding board. It would not release. I had to use a putty knife to get the spare off of the molding board. Other than losing this mold, without getting a casting, I'm in good shape. The oil-clay arms were not damaged. I washed them off with cold water, and they are ready to be molded again.

This is the biggest moulage mold I have ever made. It had 9 pounds of moulage in it. Even though I made the coddle as tight as I could around the oil-clay arms, there were still some very thick mold sections between the oil-clay arms. In the center of this moulage mold, there was moulage that was still liquid. I am going to have to design my moulage molds better, with no more than one inch thickness anywhere in the mold. Fortunately, the moulage is reusable. The only thing I have lost is some time. In return, I have gained a valuable lesson. I think the tuition was just the right price.

I guess I will try a two-piece mold next? I still have ideas of making one-piece molds. Maybe just one arm at a time? I still have to cut this moulage mold into pieces. Right now, the mold is split up between the two plastic buckets it came in. The lids have been fastened down securely, so the moulage will not dry out.

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