[Avodah] A "Coal" of Metal

[Chana Luntz]

RMB writes:

<<The following is wrong, just explaining my hava amina: I would have
thought that heating metal to anneal it would be bishul. You're changing
something using heat, which sure sounds like cooking. Whereas heating it
until it glows would be havarah, as the physics isn't /that/ different
whether it is air glowing or metal glowing.>>

Are you sure that the Rambam isn't assuming that when you heat metal to
anneal it you are not in fact making it glow?  Maybe he would say - well of
course, that is just how it is done.

Whereas in the case of it going to a "coal" or melting, is it necessarily
the case that it is glowing?  Coal I would have thought of as blackening,
not necessarily glowing.  And it has to be a form of blackening that is
useful, otherwise it is destructive.

Because if in fact the Rambam is making assumptions about the way annealing
worked in his day (to glowing) and assuming that the focus on melting or
making a coal is on the product, and it doesn't necessarily need to glow,
then wouldn't it just work?

Tir'u baTov!
-Micha

Regards

Chana