Curious as to what "half strained" means, also the "mordant" in mordant sheep, revolving around getting darker colors. All I've found was that a number of different chemicals (acids etc.) were used as a mordant in tanning sheep leather. Living in a different part of the world, many of these once common terms have faded. I have a fantastic book called "fortunes in formulas" that is full of old chemical names. You have to work to figure out what they are referring to. Hint, if you break your meerschaum pipe, glue it back together with garlic juice!
Just picked up om this thread, its about valves for big reeds?
I do a lot of work with Baritones, having re-valved no less than three in the last six weeks.
I have also been offered half strained leather for hand cut valves, indeed I took a delivery of half strained leather pre-cut standard valves. Half strained is just too stiff and inflexible for standard valves, and not much better for hand cuts. I rejected several £100's of valves back to the supplier who sent a load of samples of alternatives, none of which I was really happy with. (I suspect we are using the same supplier Alex,) The original leather I used to get was was Mordant sheep.
On big reed instruments I have seen synthetic valves, which were less than successful when playing pianissimo. Thin rubber insertion which had the same problem but just killed all resonance. I have also seen valves glued together full length. Valves with another valve as a part length backer. all of which lacked play sensitivity.
The trick is in valve springs, I use the same spring wire as a coil action springs from, and fit them in a similar way to the heavier OEM valve springs. but at a shallower angle to that the maximum opening is about 50% more than the valve pin height in the mating chamber. In the chambers valves are constrained by two or three pins, usually positioned to restrict the valve on opening so it can fall back or be easily drawn down by airflow to cover the reed pan vent. The valve spring is there for the same purpose, not the same way as an accordion valve vire works.
Hope this helps
Edited by Dana Johnson, 05 June 2017 - 05:00 PM.