Hi,  Al Pebworth was kind enough to tell me about the synthetic pouch
sealant years ago.  I owned a Welte upright which had the pneumatics
recovered but nothing was done to the pouches, which were pretty dried
out and sluggish.  The piano did not do a good job with repetition at
all, nor did it close its valves well during playing strokes (Autopiano
action).

After careful wipe-down with the sealant recommended by Mr. Pebworth,
the piano pretty much sprang back to life and became much more
articulate.  It also gained markedly in expression.  I'd planned to
replace these geriatric pouches, but as long as they perform, I'll hold
off.

Leather varies from cow to cow, so it all has to be checked.  The
sealant is, if nothing else, insurance -- it doesn't do any harm but
could do a world of good.

Tim Gautreaux