You might like to try this. You will need:
- A metal canister open at one end a little bigger than your pot.
- Two pieces of chipboard big enough to cover the end of the can.
- A brick or two.
- A newspaper about 1/4 inch thick.
- A bucket of water.
- Rubber bands or string.
- Some charcoal.
- A plastic shot glass or similar.
- Some alcohol (UL meths, US ??)
- Place the first piece of chipboard on the ground, with the tin on top. (This insulates the tin a bit.)
- Cover the bottom of the can with charcoal.
- Put the newspaper into the bucket of water to soak.
- When it's getting nearly time to take the pot out of the kiln take the newspaper out of the water.
Let it drip a bit then wrap it round the chipboard and secure it with the rubber bands or string.
You should have a nice flat region of paper that will securely seal the lid of the can.
- Fill the shot glass with meths.
- Take the pot out of the kiln, and place it in the tin on top of the charcoal. Keep it away from the sides.
- Pour the meths into the tin. [H&S keep your head well clear, and wear something like a leather glove.]
- Place the wet newspaper over the tin to fully seal it.
- Put a brick or two on top to ensure the seal it good.
WAIT until it cools. Then open the tin. You should be surprised how big a vacuum has been generated,
and the tin should have left a clear compression ring in the newspaper.
Hopefully the pot should be reduced.
If it was a copper-matte "glaze" you may have reduced it so far that there is a layer of metallic copper. You
can carefully reheat this in an oven and watch the colours develop. Unfortunately they fade with time.
A tin may be too weak and implode with the vacuum. I used stainless-steel tea-caddies from a charity shop.
You may want to try reducing the degree of reduction. You might try less meths, open sooner, etc.
PS-2 I've explained [sic] my limited understanding of copper-matte glazes in post #5 of
PP-3 Dedicated to the memory of Heath Robinson.