"LLBrown" wrote in message
...
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

It isn't plating. It's de-zincifying the brass. Muriatic eats zinc fast and
leaves a porous copper mess behind, which is very weak. When you buffed it,
you polished right through the porous copper again and got down to the
parent metal.

--
Ed Huntress