Re: Re: Question for UK players


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Posted by Chuck(G) on February 24, 2004 at 12:14:45:

In Reply to: Re: Question for UK players posted by When I had my valves on February 24, 2004 at 11:52:32:

I don't know. It would seem that any future wear on the valve would occur more on the softer copper piston, rather than the harder brass casing (the reverse of what happens with a nickel-plated piston). I've seen old tubas with what appear to be factory-original copper-plated pistons; corrosion didn't seem to be a problem.

Plating copper is inexpensive relatively simple. When a piston is plated in nickel, it must be first plated in copper, then machined to the desired size (less a small amount to account for the final plating), then nickel plated. The usual procedure is to measure the casing and have the piston plated slightly larger, then machine the casing to fit the slightly oversized piston.

But with a piston plated only with copper, it would seem that the casing need only be machined to remove any out-of-roundness and corrosion; the piston could then be fine-tuned to fit the casing.



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