Posted by Mark Heter on September 03, 2003 at 21:38:11:
In Reply to: Re: Re: Re: Alternative horn materials redux posted by ooooh! on September 03, 2003 at 07:37:34:
There have been several experiments with alternate materials for valves, especially over the years. So far, they haven't come to much. Selmer and Olds put out a plastic valve casing, and manufacturers have experiemented with a Nylon derivative called Delrin for the valves themselves. Some readers may remember Giardinelli making mouthpiece rims out the stuff (I had one - it was great in cold weather).
The problem is temperature. As you play, the horn's temperature changes. The pitch changes, too. The problem mainfests itself in close tolerances (piston to valve barrel clearances) when you have two different materials reacting at different rates of change to the temperature changes. Plus, you have to get to seal as well as move.
I'm sure manufacturers would love to stop paying craftsmen to solder and braze together valves and valves sections - and replace them with injection molded and extruded plastic parts. So far, nobody's gotten it to work.
There probably have been some patents filed on this, but I know of nothing that has stayed in production in this regard.
The biggest improvement in valves has been a stainless steel alloy called monel; these are not found in too many tubas. Walter Sear's designs for the DePrins tubas (1960s) made under his name (these turn up on Ebay from time to time)incorporated stainless steel valves, which worked very well. Walter doesn't get enough credit for this. These horns, which are now not fewer than 30 years old at this point, turn up, well-used with perfectly sealing/moving valves after years of hard use.
As I remember it there were big problems when Meinl first made stainless steel (or monel, I'm not sure which) valves - they couldn't get them to seal. Couldn't master an already acheived technology....
MH