Martin Sigley has some good information on how to rebuild these old
wind motors. Most of the steps that he describes are very good but
here are a few steps that I do differently.
Step 20 indicates to lubricate the sliding valve surfaces with
denatured alcohol and powdered graphite. I find that this doesn't
work and the powdered graphite doesn't adhere to the wood at all.
What does work is using isopropyl rubbing alcohol and powdered graphite
to lubricate the surfaces. The water in the rubbing alcohol helps open
up the pours of the wood so it can accept the graphite lubricant.
Martin, go ahead and try it and you will be convinced that isopropyl
rubbing alcohol is the way to go.
Step 7 (cracking off the pneumatics). If the pneumatics were
originally glued with animal hide glue that is now 80 years old,
then they can be removed with little damage using a knife as Martin
describes. But if someone has done work on them using modern glues,
then you will certainly do more damage during the removal. Most of the
time the worst damage is to the back of the slider manifold. I usually
just take it for granted that the bottom boards of the pneumatics will
be ruined anyway so I just make new ones. My procedure takes a long
time to do but it has always worked with no damage to the gluing
To remove the pneumatics, measure the span and write in down. Use
a razor blade or knife and cut the 5 movable top boards off of the five
pneumatics. Mark each movable board with numbers so they can be reused
and glued back in the same order as originally built. You are now left
with the 5 bottom boards that are still glued and overlap the edge of
the manifold. Measure how far the top and bottom of the pneumatics
extend beyond the valve reservoir and write this down.
The next step is to remove as much of the old pneumatic wood as possible
without disturbing the mahogany gluing surface. Use a band saw and cut
the top and bottoms off of the pneumatics so they are fairly even with
the edge of the top and bottom of the manifold. Just be sure that you
don't take off any wood on the top or bottom edge of the manifold.
Depending on what tools are available determines the next steps.
1. Use a chisel or plain and shave the wood down 1 layer at a time.
Remove all of the poplar wood of the pneumatic. You stop when you hit
the glue surface. Be careful of any nails that may have been used to
align the pneumatics.
2. Take a table belt sander and sand down as much of the old pneumatic
wood as you can. I usually leave a thin layer of the old poplar wood.
Sanding into the glue just loads up the sandpaper and you run the risk
of sanding down into the bottom mahogany layer.
3. Remove most of the remaining pneumatic wood using a table saw. I
have done this safely but don't suggest that it be done unless you know
what you are doing. There is a big chance that the thin pieces of wood
will jam between the blade and the base of the table and fly back into
your face. It's best to go with the other 2 suggestions.
Once you get close to the level of the glue, you can moisten the glue
and/or wood and use a sharp chisel to get down to the original gluing
surface. Take a small glass of water and dip your fingers to get them
wet. Now with your finger transfer the water to the glue or wood
surface. Wait about 10-20 seconds and then scrape off a thin layer of
the remaining wood and/or glue. By doing this process very slowly and
being very gentle, the chisel shouldn't gouge the wood.
The secret here is to not force the chisel into the wood or glue. If
it doesn't want to come off, just wait a while longer and try again.
If the chisel does start to gouge the mahogany wood, moisten the area
again and bring the chisel in from another direction. Repeat this
process until all of the glue has been removed. When all of the glue
is gone, let things dry out and lightly sand using 80 grit sandpaper.
Now you have to make new bottom board to match the original top boards,
glue hinges and recover the pneumatics, seal and follow the other
directions found at http://www.goldcoastpianos.com/WindMotorRepair.html