LLBrown wrote:
"Ed Huntress" wrote in message
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"LLBrown" wrote in message
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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?


It isn't plating. It's de-zincifying the brass. ...


Thanks for your answer, I would be 100% convinced that your answer is
correct except this doesn't happen when the muratic acid is a new clean
batch. Why would that be?


My first guess would be a lack of observational rigor. Coupled with
slight differences in the situations, e.g., length of exposure.

The idea that "... acid is leaching copper and plating later pipes ..."
doesn't make sense. Why would it leach one, but not the other & why
would it plate one, but not the other?

"de-zincifying" is what I have always heard is happening. In support of
this is the fizzing that takes place. This is the hydrogen being
released from the muriatic acid (HCl) as zinc chloride is being formed.

Also not a chemist,
Bob