Duo-Art Valve Pouches
by Mark Fudge (030122 MMDigest)

mfudge_pouches.jpg (42 kb)
[Larger view]

I'm currently trying to solve a vacuum loss problem on a 1922 Weber pedal-only Duo-Art, or "half Duo-Art" as they seem to be known in the UK.  Through testing each component I eventually traced the suction loss problem to the player action stack itself.

The cross valves seem to be in good order and there is no obvious damage which would suggest that facings, etc., are causing the problem.  However the pouches seem to have been replaced at some point and don't seem to have the "mobility" of original Aeolian pouch leathers, and I suspect that these are causing a significant amount of loss.

The attached picture shows that the pouches have crumpled somewhat, and some have almost developed a tendency to spring, thus preventing the valve to sit correctly.  I'm wondering if the leathers have dried, and also what may remedy this situation.  I'm loath to replace a whole set of pouches and ideally see this as a last resort.

There were also two other possibilities for suction loss.  The striking pneumatics appear to have been glued on without any paper gasket, and each deck had been sealed with a form of sealing tape similar to duct adhesive which had, I suspect, started to lose it's ability to hold vacuum effectively.  I'm planning to replace this with the normal rubberised cloth.  Do these sound viable as a source of vacuum loss, and is it safe to use a sealant tape?

I'm also trying to locate a supplier for the small collars which fit to screw heads which are used to fix the pouch board to the valve deck and seem to prevent the screws from "digging" into the wood of the pouch board itself.  Any ideas?

Mark Fudge
22 Jan 2003 19:08:55 -0000


12 February 2003