How to use two simple ingredients to make your own self hardening clay.

This technique is given in both the Castcraft Guides and the Castcraft Moldmaking Video, but it is valuable enough to mention again: By adding ordinary kitchen baking flour to plaster, you can make the plaster into a "self-hardening clay" type material.

Here are just a few things you can do with it:

  1. Make sculpture you can work by hand or tools for hours. Then in 24 hours it will harden and your sculpture will be permanent. But you can still carve and sand it.
  2. Use the material as a spackle to repair defects or fill holes in a model. You can press it into place and it will stick. 24 hours later it will be hard and permanent.
  3. Use it to make "walls" or "containers" to surround a model you will be making a mold of. Just form the material into any shape you need. 24 hours later you will have a mold box, more permanent than clay.
  4. Make your own custom, reusable, mold box walls: Roll the material (see this tip) to a thickness of 1/2 inch to 3/4 inch, then cut into strips as wide and long as you need. 24 hours later you will have a set of permanent plaster "walls" to surround a model and make a mold box.

Here's how to make the self-hardening clay:

First, mix an ordinary batch of pottery plaster. Then, while stirring, add as much flour as it takes to turn the plaster into a stiff clay-like material. To use the material, take as much as you need and knead it in your hands for a while until it is very well-mixed and uniform. Then form it into any shape you want. It will have a workable time of at least a couple of hours. It will be completely hard within 24 hours.

Remember that this material is still plaster! To avoid plugging up your plumbing, don't wash your hands or tools in a sink - use a wash bucket or outside faucet!

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