WURLITZER 105 RESTORATION PROJECT (Part 6)
PNEUMATIC STACK RESTORATION
By Dr. Bill Black
This month we will look at the stack restoration. We have the complete
set of pneumatic unit valves and the front face for the stack. We are
lacking the vertical section of the stack which has the vacuum channels
to supply the valves and the channels to the pneumatic. Also missing is
the deck on which the pneumatics are mounted. Mike has fabricated these
two pieces using as a guide the spacing of the windchest channels and the
front face where the valves are mounted . The piece with the vacuum
channels is the most difficult one to fabricate.
The next step is to fabricate the pneumatics. Photo A shows the steps
involved in making a pneumatic. The top and bottom of the pneumatic are
cut from a strip of poplar wood. From left to right, the two pieces are
hinged with a piece of pillow ticking, the front of the pneumatic is
glued to the strip of pneumatic cloth, the two sides are glued, the hinge
end is glue last with an overlap of the cloth and the excess cloth is
trimmed from the pneumatic. I use white glue for this procedure. Birch
was used for the little finger on the pneumatic which contacts the
Photo B shows the back view of the assembled stack with the pneumatics
now glued onto the deck with hot glue. Care must be taken to be sure that
the spacing of the pneumatics is correct so they will all line up with
the windchest pushrods.
Photo C shows the front view of the stack with the unit valves restored
and mounted on the front of the stack. The nipples for the hoses to the
tracker bar are not installed yet.
In Photo D we now see the stack which has been mounted into the organ.
When the pipework is installed, we will not be able to see the stack from
this aspect again. So, this is a good chance to see the relationship
between the pneumatic stack and the windchest. When the unit valve
applies vacuum to the pneumatic, the pneumatic collapses and pushes the
wooden dowel rod downward. This opens the pallet valve inside the
windchest to allow the wind to flow through the channel in the windchest
to cause the pipe to speak. An ingenious arrangement..........
Dr. Bill Black is one of the nation's most knowledgeble Wurlitzer band organ experts. He has made recordings of many band organs and other mechanical music machines which are available for purchase at CarouselStores.com.