Simplex Pedal Muffler Felt
By Craig Brougher
|Brett Mohr asked about the felt muffler over the Simplex pedal valve. That, I believe, is called muffler felt and probably either glued to a little frame, which in turn is screwed down to the valve block, or possibly just glued or tacked directly. You can buy muffler felt in different thicknesses from a pipe organ supply company, but for a little piece like that, I wouldn't worry. Build it up with a few pieces of felt laid on top of each other, punch a circle of very small holes through the stack and one to clear the valve stem, and tack it down around the pedal valve with about 4 very small #1 tacks.
However, a valve should not ever hiss, otherwise, it is leaking. The only sound you should ever hear from a valve is a faint transit slurp when its pneumatic relaxes. Hissing when actuated means either 1) the pouch cannot raise the valve strongly enough, 2) there is a leak between the outside valve seat and the pneumatic, 3) the valve is not seating against the outside valve seat. These would not prevent the pedal from working, necessarily, but the muffler felt described is really more just to keep dirt out than to prevent noise.
Just remember, any leak that hisses is a small one.
(Message sent Thu 3 Oct 1996, 13:59:41 GMT, from time zone GMT.)