another reason why exotic valves might not be good for tubas

[Dan Schultz]

Those 'hockey puck' CL valves just suck! A few years ago, a customer came to me with one the early ones where the rotor was riding inside a plain brass casing. C/S actually honored a warranty and replace it with one with a nickel-silver (stainless steel) housing. It appears that some the early stuff must have been trash... or at least released without much thought and prototyping.

[Lee Stofer]

It seems to me that if you place aluminum against any copper alloy, dissimilar metal corrosion will make a real mess of things, just as mixing aluminum and copper wiring in an electrical situation is a real no-no.

I think the Kanstul patented Controlled-Resistance valve is about as exotic as it gets without real troubles, and it is all-brass.

[J.c. Sherman]

Those CL valves offend my every sensibility.

Anodized aluminum is used in some Thayer valves too... the corrosion that occurs on those in their brass housings is not to be believed. I've only been able to patch the holes with an epoxy fill... I'm waiting for the spindles to break on several sets so we can put a bullet in them.

Had an interesting visit from an earlier CL valve owner for a playing condition. Inside of the brass housing was what looked like a carbon composite rotor. it weighed nothing and was in perfect shape (except for it's counterintuitive design...). Fastest valve service I've ever done...

J.c.S.

[ralphbsz]

Of all common metals, aluminum sounds like the most inane choice for corrosion resistance in a wet environment. When I was a grad student, I worked on deep ocean stuff, and we had to use aluminum housings (because we couldn't afford titanium). Corrosion protection was a huge deal, with careful anodizing (doesn't work if drilled or when parts slide past each other), industrial-strength coatings (marine paints are amazing), and huge sacrificial zinc anodes. I've seen inch-thick pieces of aluminum run into a sponge within a few weeks in seawater, if left unprotected and in contact with other metals.

The idea of using aluminum inside a brass instrument sounds pretty dangerous.