shocker wrote:
PS Forgey-
please do us a new thread on making blades from files/HSS and the like, I dont have the reference books anymore, most of the info online is BS and my memory is crocked

Third times a charm....
I'll post in Tutorials sometime in the next week or so.
To be going on with there are three main types of
Heat
Treatment. (I'm going to start with the fundamentals so we're all on the same page

)
First theres Hardening (usually paired with Tempering), Hardening makes the steel hard and brittle then Tempering makes it a little softer and a little tougher. Heat and cool rapidly to harden, bring back up to a lower heat to temper
Then theres Normalising which relaxes the stresses caused by bending and forging (these are sometimes called 'Work Hardening', at times you'll want this and other times you won't)
Heat and allow to cool at room temperature.
Lastly theres Annealing, this makes the steel as soft as possible. Heat then cool very slowly (I tend to bury the piece in dry sand)
[/nerd]
Shocks: The material you're talking about is Thermalite, commonly used in the building trade for the inner skin of a cavity wall. Available from builder's merchants in a range of thicknesses...... Not thought about using it as a hearth
