Thursday, 31 March 2011

Mould Making

Today I arrived at uni, with a mission: to make a cool mould for my new pair of hands. I made the mould, but it wasn't cool. Here are my steps:

 I placed the pair of hands on top of a block of water based clay.

 Then, I raise the clay  half way up the hands, in this picture I've done the first 2 fingers :

I continued with this long an precise process until I had both hands covered in clay up to half way. Once that was done, I stack a couple of "keys" that have the shape of a weird pyramid that will help both sides of the moulds stick together in the right place:

After a quick spray of Crystal Clear, I built the walls around the clay:

And we are ready to pour the plaster, in this case Keramicast, but I made sure I mixed it really well for almost  ten minutes so I achieve the hardest plaster possible:

Once the plaster is set, I took the walls apart, and I got something like this:

And now, I removed the clay. Here I had some difficulties: The plaster, as it sets, reacts giving out quite a lot of heat, and the platicine the hands are made out went really soft because of that heat. As a consequence, a little finger got ripped off, and some detail was lost when I pulled off the clay. For next time, I'll just let the whole thing cool down a bit, so the plasticine hardens again:

The next step is to clean off all the clay left in the first part of the mould, and rebuild that little finger. Special attention needs to be paid in the line where hands and plaster meet:

After cleaning all the clay, I build up the walls again, rubbed the plaster with vaseline all around the hands, put a couple of blobs of clay on the edges (this is to stick two screwdrivers and pull the two parts of the mould apart) and poured plaster again. Waited until it was set, and pulled the two parts of the mould apart. (The pictures from now on are from a different mould I made about a month ago):

You see in that picture there are already two hand armatures that fit in the mould. Also, notice that from the wrist, there are two holes that go to the edge of the mould. Those holes are where the copper tubing for the replacement mechanism goes.They are also the point of reference to where the armature is going to fit.

All there is to do from now, is to mix some foam latex , shove it in the kiln for a couple of hours, and this is the result I get:

You take it out of the mould, gently, Here I had a picture of a cast I made in regular latex (not foam)to give a reference of the sacale I am working on:

Now, all I do is trim all the remaining latex around the edges, and my hands are ready to ....snap!!
Tomorrow, a lot of armature making.... (boring)

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