Friday, September 28, 2012
06 Waste Molds Nº 18
First of all, it is necessary to find a block of time large enough to do everything. Everything means melting moulage, pouring moulage, waiting for moulage to set up, and repeating the same thing for the other side of the mold, then melting and pouring carving wax. This is a photo of the first side of the moulage mold poured. Notice that the wire of the oil-clay arm armature is sticking up through the moulage. Click on any image to enlarge it.
I decided to make some more coddles that would fit this mold better. Here are the pieces after a coat of shellac. The large piece of wood is going to fit over the first half of the mold, so I drilled a hole in it for the armature wire to fit through it. I figured this stuff out as I was working on the mold.
I covered the moulage with a plastic bag while it was cooling and setting up.
The first half of the mold with the oil-clay arm embedded in it. The clay build-up came right off. Look at that registration key. I need to add some clay to this side of the spare.
I forgot to make a top for the new coddle, so I did not get a chance to shellac it. Here is the first half of the moulage mold, oil-clay arm embedded in it, with the bare top, banded with rubber bands, ready for the second half of moulage to be poured.
Another view of the first half of the mold, ready for the second half of the moulage mold to be poured. I had to add a coil of Roma oil-clay around the new top because there was a small gap, and I did not want to be fixing a leak of hot moulage during the pour.
This is the second half of the moulage mold poured. I have covered it with a plastic bag while it is cooling and setting up. The clay build-up is at the top of the photo, showing its bottom side.
After the moulage set up, I removed it from the coddle and opened it to remove the oil-clay arm. This is the split mold, showing the registration key. I used some toilet tissue to dab out excess moisture before closing the mold and putting it back in the coddle to pour carving wax into it. Each of those moulage mold halves weigh about three pounds (48 oz.).
This is the closed mold, banded together with rubber bands. I used one of the pieces of the first coddle on the back side. Right under the top rubber band are the holes I drilled for the armature wire to stick through. Yeah, I missed with the first hole and had to drill a second hole. It worked.
This is a bird's eye view of the moulage mold, ready to be poured with carving wax.
The carving wax was melted and poured into the mold in one steady stream of molten wax until it topped the pouring hole (the spare). The carving wax is thickening around the walls of the mold and sinking in a little bit. This part is critical. I want the carving wax to get thick, but not too thick because I want to be able to pour the excess wax back into the wax pot. If I wait too long, the hole will close and I will not be able to pour anything out.
I hope I got it right. I was able to pour some excess wax back into the wax pot. I do have a hollow casting of some kind.
I have filled the hollow carving wax casting with cool water to help it cool.
This what all the work was all about. I have translated the oil-clay arm into carving wax using hot-melt moulage , a reusable molding material. Here is the carving wax arm, with the moulage mold opened.
And here is the other side of the carving wax arm. The moulage mold is semi-flexible, so I do not have to worry about undercuts too much.
The carving wax arm is still warm, so I am soaking it in some cool water in the studio sink so it will cool down faster.
I wrapped the moulage mold up in plastic bags so it will not dry out. Tomorrow I will cut it up into small chunks and store it in Atlas Mason jars with tight fitting lids. I want to add that my mold arithmetic was just right. I melted just the right amount of moulage for each half of the mold.
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