Gulbransen Repairs for Todd
& Shannon Kutz
When we made the initial service
call to diagnose the problems for the Gulbransen Player Stack and Bottom
Unit, we found that it was very hard to foot pump, and with the vacuum
running full speed, there was a loss of notes on the high end of the keyboard.
Removing the upper unit from the piano and checking for tightness of the
covers and gaskets led to no change. The tracker tubing was getting
hard and several tubes broke when bending the upper part of the stack forward.
We decided that the best option was to bring the upper unit back to the
shop for further testing. The lower unit was tight, so we left that
in the piano. The pictures below show some of the steps in resolving
Referring again to the above
picture shows the three layers of the stack removed from the player and
sitting on the bench. The picture shows numerous valve covers missing.
These were partially loose, and you could just put a fingernail under the
edge and pop them loose.
Most of the loose valve covers
showed signs of severe leakage under the loose part for a long time.
Another example of the leaking
covers. When the player would operate one of the valves with the
leaking cover, the force of the rising valve would tilt the cover up, allowing
outside air to come into the system. Over a period of time, this
led to the dirty build up as seen in these pictures. As multiple note with
the leaking covers were called into play, the vacuum in the upper half
of the stack would drop, preventing the notes from playing.
Because of the many loose covers,
and the general condition of the valves, it was decided to do a restoration
of the pneumatics and valves, and to re-tube the player.
The pneumatics were sheared off
after removing the remaining covers and valves and stems. Because
of the general weakness of the glue (Appeared to be watered down hot glue),
this did not present any problems. There were some chips missing,
which were filled before covering. Above picture shows board with valve
cover and valves removed, and a board with it's pneumatics, showing signature
of some prior re-builders.
Two of the 88 pneumatics after
removal and repairs to chipped wood. Note the light area between
the pouch well and the opening to the pneumatic.
The three layers of the stack
after pneumatic removal and clean-up. The brass valve seats were
also loose, and required removal and cleaning, then re-gluing in place.
Upper part of pneumatics with
newly resealed pouch well, and all chips repaired, wait for the shellac
on the movable leaf of the pneumatic to dry, and to be hinged. But
first, the new pouches have to be installed and sealed. Yes, the
remote is for my TV, my connection to the outside world.
Applying "Fish Glue" to the perimeter
of the pouch well lip. Some re-builders use hot glue for gluing the
pouch, but I prefer the fish glue. It gives you more time to set
the pouch, especially if something interesting should come up on the television.
Try to apply the glue to the extreme
perimeter to prevent glue from being applied to the portion of the leather
pulled into the well as the pouch is dipped.
New leather pouch laid over
Next I lay a small square
of plastic wrap over the pouch.
Custom sized pouch setter is applied
to the pouch. The plastic wrap prevents seeping glue at the edge
from getting on the setting and making a sticky mess. There are numerous
other ways to set a pouch, but on the recessed lip of the Gulbransen, I
prefer this method.
After removing the pouch setting
tool, you can use the eraser on a pencil to finish smoothing the edge of
the pouch if required. No glue on hand.
Finished, but unsealed pouch.
You may notice that I have enlarged the hole in the end that connects to
the tracker bar. This will be explained in a later step.
Enlarging hole in board to
match that enlarged going to the pouch
Enlarged hole and sealed pouch
Small piece of thick wall tracker
bar tubing, with one end cut on an angle, inserted and glued into enlarged
hole on board, using fish glue. The angle cut prevents the tube from
blocking the opening to the pouch. After drying, I use a tongue depressor
with a slightly larger hole, held over the tubing, and a razor blade to
cut it even with the top of the wood of the depressor. Sorry, I did
not get pictures of this step, but will include in the full article on
the restoration of the Gulbransen.
Pneumatic slipped over the rubber
tubing for test fit. I put a thin film of hot glue glue on the board,
covering three or four pneumatics at a time. Then apply the glue
to the back of one pneumatic, slipping it over the rubber tubing, and aligning
with a combination square so it is square with the edge of the board.
Press down firmly with fingers, and go to next pneumatic. In a warm
shop, you can do three or four at a time. When the glue on the pneumatic
hits the glue on the board, they meld together and hold without the need
of a spring clamp.
One row down, two to go!
End pneumatics were sealed off in a prior rebuild, resulting in a total
of 82 functioning pneumatics.