I have rebuilt several of these items since my last posting on these
valves, and I have found a better way.

The natural gum rubber works well but I had trouble getting them to
relax.  The product comes in a roll and the discs are shaped like
biscuits.  The discs I cut out to put in the valve blocks have trouble
laying flat: some of them cup.  If someone knows how to relax this
stuff, let me know.

In the future, I would make up valves using some of the tested airtight
leather I have, with some cardboard discs stacked up and glued.  I will
still use my dies with the pin prick in center to cut the leather, so
that I have a place to drill the center hole for an escutcheon pin
glued into the plastic valve stem.

However, I most recently restored one of the Kaps orchestrions made
from the same Aeolian instrument using Denis Wilkinson's brand new
plastic valve blocks.  I found it so much faster to do this rather
than rebuild the old ones.  I kept the old ones.  I will rebuild them
someday as well.

I also replace pouches on these since I don't trust the 30-year-old
leather.  I also do not leave the sponge Neoprene discs on the pouch
but make new cardboard and felt ones like in Ampico blocks.

When using the new valve blocks, it is advisable to use a board with
sandpaper bonded to it and lay the open side of each block down and
sand it for several seconds.  The three pieces do not always line up
perfectly but, more important, sanding roughs up that side of the
plastic and makes it stick to the plastic glue better when you glue
them on the stack.

I plan to use these valve blocks to build my own stacks.  The valves
that come in these are a silicone rubber that seems to work very well;
it is totally airtight.  However, if I build a stack for an Ampico or
other reproducer, I think I will make my own from leather as described
above.  I notice they have a slight flex under high pressure so I would
feel better for reproducing piano uses to have leather I have tested
to be airtight.

D.L. Bullock    St. Louis
www.thepianoworld.com