How long does it take to dry burnt shellac holding a valve seat into
the block (similar to a Wurlitzer valve unit)?  I was thinking it
should be about a week.

I "re-glued" one using some burnt shellac that has been sitting around
for a while (years).  I did this in mid-December.  I went to test the
unit this week and the valve wouldn't stop leaking.  When I took it
apart the valve had pushed the seat out of place because the burnt
shellac was still quite soft.  Wouldn't hold a darn thing.

Dave Clark