Posted by Steve Inman on February 01, 2001 at 21:40:32:
In Reply to: Re: Re: Re: cryogenic tuba freezing posted by Rick Denney on January 31, 2001 at 22:45:21:
A while back on the tubaeuph forum, there was a lengthy thread about heating/cooling/annealing instruments. I think I was supposed to contact a metalurgist at my place of employment and provide some final, definitive answers to several questions. I half way succeeded, providing some feedback, but never a final summary statement so several follow-up questions. It was all getting rather technical.
I do recall that the statement was made that deep freezing/thawing of brass metal does not change the property of the metal at the atomic/molecular level. Only heating/cooling will do this (annealing) and this requires careful control of the time/temperature profile to get the results you want. This of course carries the risk that you'll melt the solder in multiple places and end up with a nice collection of various sized/shaped brass tubes when you're done.
My personal "research" in talking to a guy with a BS in physics and an MS in metalurgy leads me to conclude I won't ever bother wasting my money with a freezing treatment. I would predict you'll notice a more significant change in the performanc of your tuba by simply buying that new mouthpiece you've always wanted to try. Probably quite a bit cheaper as well.
Steve "if I lived in Florida, my tuba would seldom even see freezing" Inman
Kokomo, IN