Chapter 8.2 - Recovering The Tempo Regulator
Being a pressure bellows, the regulator cover is gusseted. Using the old gussets as templates, cut new ones from medium cardboard.
The covering is regular pneumatic cloth, but a long piece, about four feet, is required. This is stretched long wise, and a horizontal pencil line is drawn across the whole length. Using the old, torn off cloth as a guide, trace the positions for the new gussets on the cloth.
Mask and glue on the gussets, applying hot glue to both the cloth and the cardboard to insure good adhesion. Moistening the backs of the gussets with a damp cloth equalizes the swelling of the paper on the glued side, and keeps the cardboard from curling up while the glue sets.
Just like on the feeders, the fold along the center line of the cloth is reinforced with strips of muslin, to keep the crease tight.
The first covering step is to fold up the cloth and place it between the boards as it will be when completed. The box is masked along the trim line. Using a small brush, glue the cloth to the ends of the bellows. The pull it tight from the hinge end, and fix the corner with a small tack. Normally one does not use tacks when using thin cloth, but this bellows is almost as long as a player reservoir, about 18", and the same technique has to be used. Subsequent manipulation of the side cloth can not be allowed to pull loose any place that has already been glued. Now lift the cloth back to the tack, put more glue around the board corners, stretch the cloth again from the hinge end, and put two more tacks near the corners, on the sides.
Make sure the cloth is folded in its final shape, and inserted between the closed boards. Working a short distance at a time, stuff glue between the cloth and the boards, and attach the sides of the cloth. Keep going back and pulling the cloth tight, both from the hinge end, and sideways, away from the gap. The edged of the gusset inside must be pulled as close as possible to the edges of the board. Work on alternate sides, to give the glue time to gel after each application. A rag wet with cold water helps to gel the glue promptly. Keep doing this until you come to the end of the gusseted part of the cloth. From time to time, the excess cloth that gets wider as one nears the hinge end can be trimmed off, to make getting the glue brush up inside easier.
Once the ungusseted area of the cloth is reached, it can be pulled back, and the rest of the board edges can be glued. The the remainder of the cloth can be stuck down and stretched long wise, just like on a player reservoir side. The cloth is finally pulled around the hinge end corner and tacked in place.
Then the hinge end is covered in the usual manner.
After the cloth is dried and trimmed, test the cover by covering all the openings in the regulator, and pressurizing it.
The the cloth is given a final trim with the flat file, and another coat of stain and shellac is applied to the entire exposed woodwork.