Clay Masters

[Little man baits]

I know some guys make their own masters and then make plastics out of them I am wondering from the clay master to the finished plastic what are the proper steps in achieving this? I have made lots of masters that o would like to recreate but need help in the following steps.

Thanks guys. Either one or 2 piece molds

Steve

[mark poulson]

I've only made one piece molds with my clay masters.

I shape the Sculpey clay, bake it hard, coat it with clear acrylic as a sealer, and crazy glue the bottom to a piece of formica.

Then I glue the wood mold box down around the master so I have enough room to get my GE Clearseal RTV silicone all around the master.

Any 100% pure silicone will work.

I put the first layer of silicone onto the master with my finger, to force it into every nook and cranny before I glue down the wood box.

Once the box is set, I mix up some silicone with a few drops of water and begin adding it around the master in layers, until the box is full.

The water helps the silicone cure more quickly, and you have to play around with how much to add, but a couple of drops mixed into a small batch works. Do a test to figure out how much.

If you have voids when you remove the box and master, you can finger in some more silicone into those, and it will stick to itself really well.

Lately, I've switched to adding the silicone with a caulking gun in layers, and dropping in the water and mixing it in place with a stiff piece of wire.

It works, but it doesn't set up as fast, because there are areas that don't get the water, but it's still faster than using straight silicone with no water.

Lately, I've been thinking about making some two piece molds using the Sculpey masters. If I do, I'll put a cut off wooden golf tee, or something similar, into the head before I bake the masters, to act as a sprue for injecting.

It's really hard, at least for me, to cut and rework the silicone after it's set.

Edited February 25, 2012 by mark poulson