Jim, Recently a welder said something to me about this, and since he was talking to me about brass rail, it zipped right past me, I didn't stop to take notes. He may have said 800 degrees, but there is probably a time element necessary as well. There may be something less severe that still functions to "stress relieve". I remember he used that phrase a few times. In sum, I'd ask a metal specialist. Thinking too, if you do this in the piano you are heating up a lot of other things, is that a problem? And if you take them all out to do it, why not replace with new? Audrey Karabinus, Seattle
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