Re: Art of the Ninja!
yeah - this is called 'case hardening'
1 plunge your piece of red-hot lower-carbon-content steel into the case-hardening compound
2 reheat the bizzo back to red-hot
3 clean the cooled work
4 harden the piece 'right out' with a red-hot plunge into cold water or brine
5 temper to desired hardness -
nah... a bike frame is a bit big, and the tubing, if heat treated already (likely) will have its strength/springyness changed, most likely for the worse...