Case Hardening with a Charcoal Furnace

[awemawson]

Back in the day, parts would be packed into an iron box with the carbon compounds and a few shavings of wood. The box lid was reasonably tight fitting and retained with a twist of iron wire - the shavings burnt up and exhausted the oxygen from within the box. Knock out was a case of lifting the box from the Furness, knocking the contents out and dunking them.

I too have used the stainless foil and as Tom said, it's razor sharp - mine must be a bit thicker than the stuff Tom was using as it doesn't burn through, but it's the very devil to get the parts out while still hot enough to quench.

I reckon a box is the way forwards.