In article ,
"LLBrown" wrote:

Here is what goes on.... I bend a thin wall brass tube to shape then I have
to melt the bending medium out of the pipe with a torch. This causes a
black scaling to show up on the outside of the pipe. To remove this I dip
the pipe in a 50/50 mix of muratic acid and water. This in turn plates the
pipe with very thin copper that I have to buff off.

I know the acid is leaching copper and plating later pipes but what is the
science behind this? Why does it plate?

LLB in Laredo



Silly slightly off topic comment. I saw recently on "How It's Made," a
trombone factory where they used simple ol' ice to act as an
anti-collapse bending medium. Just fill the brass tubes with water,
freeze in liquid nitrogen, and then bend... let them melt and tada...
bent, non-collapsed tubes. Is this possibly something that could work in
your situation? LN is cheap and with a decent dewar, you could do a lot
of these in a short time, and no ugly chemistry needed to preserve the
chemistry/tone of your tubes.


-Dan