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Mike,

+1
Good stuff.
The sintering I was making reference to was the sintering of the PTFE layer
on the surface of almost all the factory tossaway blades.
i.e. a Teflon like plastic...

There are some tempering tables for steel that will answer your question
if you search on the net.

In general if you keep the blade cooler than hot tap water you are OK.
But, this can be harder...