When he slices and dices more silicone than his own flesh, I am a happy wife indeed! (Only two small cuts to fingers this time.)
This will be a familiar sight to our friend and colleague Karen Gerhardt, for she and Barry took the same mold making workshop taught by the sculptor Chapel several years ago at the now-defunct Loveland Academy of Art in Colorado.
In that hands-on workshop Barry learned a rather novel technique for molding a soft clay sculpture. Chapel's basic message was that unlike standard art foundry practices, you do not need to cut a sculpture up into different pieces to mold it.
CUT the sculpture UP??!
Yes, I know it sounds counter intuitive! However, in a fine art bronze foundry setting, original sculptures are often cut into several less complicated parts for mold making purposes. For instance if the area between a couple of legs is tight, simply cut a leg off and mold it separately.
Now this makes a certain amount of sense when molding for fine art bronze -- all the various pieces of the sculpture will be first cast in wax, then reassembled before investment and bronze pouring. Or, they could be cast separately in bronze, then brazed back together.
But for high quality resin reproductions for model horse collectors -- no, No, NO! That approach is just not going to cut it baby.
Why the blue gloves? I'll have to ask to be sure, but I believe it's simply to keep a good grip on that little Xacto knife he's wielding in his left hand, as well as a firm hold on the silicone as he's cutting. Note how he's cutting in little back and forth zig-zags. This creates tightly interlocking pieces of mold. The effect is similar to the way in which two sheets of "egg crate" or convoluted foam interlock their "fingers". The accuracy of the mold makes up for the tedium (and occasional blood letting) that is part and parcel of this technique.
There a couple of basic approaches to molding an original sculpture that is made of a very soft material:
The “Brush Up” Mold
Mold “rubber” is drizzled onto the original sculpture in very thin layers at first, then spread on in subsequently thicker layers.
Bubbles can be eliminated by blowing compressed air along the surface of the layer of rubber before it has set up.
The early, thin layers of rubber take longer to set and are rather delicate. A thickening agent can be added to the liquid rubber to create a more viscose material for the outer layers.
A rigid “mother mold” or “shell” should be made to encase the rubber mold before you cut the horse out of the rubber.
The "Dump" Mold
The sculpture is suspended in a rigid box, mold material is poured into the box slowly.
After the rubber material has set, the block is removed from the box and cut apart.
Depending on the material that the original outer container is made from you may be able to re-use it as a mother mold. Or, a new rigid shell can be made to support the rubber.
This was the type of approach that Barry chose for "Thunder", pouring a big chunk o' silicone is simply much faster than applying many layers to a brush-up mold. A major disadvantage is that this is a more expensive method since so much more silicone is used.
The aftermath...
The original sculpture is torn to pieces getting it out of the silicone mold. But the horse was molded intact, so any reproductions cast from the mold will be in one piece.
The areas that were sculpted in wax fared much better that the soft clay areas.
Poor Thunder... no wonder he looks a bit grim!
~ Lynn
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