I tried cooking recipe 2 and 3 with the charcoal method but found they didn’t get hot enough to develop much strength. The first time I tried using them they broke from the force of the Borax expanding inside of them.

This can be a bit annoying especially since it takes some time to get them ready.

So I changed the cooking of recipe 2 through 6 with extremely improved results. If you have access to a kiln you’re all set if not you can make one real quick with some fire bricks.

They need to be cooked in a kiln or some form of kiln to around 2300 degrees Ferenhight and held near that temperature for around 45 minutes to an hour. This may sound like a bit of a tough thing to do if you don’t have a kiln however it’s really not that bad.

Once they have cooled they will sound like a coffee cup when you flick it with your finger?

Now fire up your refractory.

Get your crucible a little warmed up before you put it into the refractory by placing it on some hot coals.

Melt the heck out of some metal !

So far my favorite recipe is number 6.

Clay crucibles can handle the heat but you do have to treat them a little different then a metal crucible.

Temperature shock is a problem for clay.

It seems to be pretty easy to address by simply setting the crucible on or in some hot coals after use so it can cool slowly.

If a crucible cracks you will want to stop using it.

You don’t want a crucible full of lava spilling all over you, do you?!?