Posted by Peter C. Hirsbrunner on January 13, 2000 at 10:05:02:
In Reply to: Re: problems with hirsbrunner rotors posted by John Swensen on January 12, 2000 at 16:17:36:
Dear Sirs
Consirning the Hirsbrunner rotary valves, I think the best is if I correct somme false oppinions directly.
The Hirsbrunner rotaryvalves are not made only from plastic. They have a bronce jacket, with a gauge of 3mm. The heart is a special plastic, called Tryplen. The axel is made of germansilver. It is true, that this valves make problems when you have to play in hot weather or in hot concert hall. This problems can be solved with a special process. Please contact me directly, the describton is to long to put in here. Contact us under contact(AT)hirsbrunner.com.
It is true that Hirsbrunner made experiments with Titanium valves. Instruments with Titaniumvalves are sold only in Switzerland, between 1963 and 1969. Hirsbrunner quit to use Titaniumvalves in 1969. The Hirsbrunner company will never make Titaniumvalves again, because the material is to expensiv today and it is very difficult to cut Titanium. Also you need a very special lubrication to oil the Titaniumvalves in Brassinstruments, which is very hard to get on the market.
Hirsbrunner did never made rotaryvalves from steel.
I hope this answers a lot of questions.
With my best regards to the list
Peter C. Hirsbrunner