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 windchest pushrod.

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.