Schomacker Piano Rebuild Page Two
See the bottom of this page for thumbnails of the pictures - - click on the number of each step to go directly to the picture it describes:
10) Here, the pin block has been removed. The sound board had already been dried in preparation for shimming in this picture. Also the shims had been installed. The technique involved in shimming sound boards today in my shop involves the use of a special die grinder jig with a trimming bit that makes a groove in the sound board's cracks. This groove fits the shimming material perfectly. The spruce shims are all selected and dried by Andre Bolduc, the foremost maker of sound board material in the world today, in my opinion. I now use either aliphatic resin glue or hide glue when gluing in shims. The shims are then trimmed with a block plane and sanded smooth. Many rebuilders will then color the shims so that they will match the orange stained sound board. I prefer to bleach the sound board so that it and the shims both look nearly new.
11) Here, the wood plate bushings are being removed. Many rebuilders will leave the old plate bushings in place and build over them when refinishing the plate. Then they will reinstall the plate and restring the piano with the old bushings in place. This is a time saving technique on their part. While this does not usually lead to a cosmetically unattractive result nor does it technically do any harm to the tuning stability of the finished product, I don't do this. I like to have the plate bushings drilled out so that the tuning pins fit VERY snug inside them. The old bushings will contact the tuning pins but will not hold them very snug. Also, when the piano was new you could look inside and see fresh wood around the tuning pins. If the old bushings are reused then you see old wood bushings with gold lacquer on them. While this is not really unattractive, it isn't very SLICK either. I prefer to have a finished product that is difficult to tell from brand new in every possible respect.
12) After the old plate bushings are removed, the pin block is fitted to the plate. In order for the piano's tone to be at its best and for it to hold its tuning well, the block of wood that the tuning pins are driven into must mate with the cast iron plate perfectly. To do this, I coat the metal of the plate with a black powder. Then the pin block (which has been roughly cut to size) is held up to the plate and tapped with a hammer to drive it into the metal. The wood then picks up bits of black wherever it touches the plate. The blackened wood is then removed until you have solid contact between the plate and the pin block over the entire surface. After I have made a VERY good joint with the plate, I use a very small amount of very high grade epoxy to coat the mating surface of the pin block. Then, using clamps and a thin nonstick barrier to keep the wood from gluing to the plate, I press and clamp the wood to the plate. This squeezes the epoxy into the last few voids that remain. The end result is a total, 100%, contact of wood to metal.
13) Here the plate is being washed to remove years of accumulated dirt. The process of refinishing the plate is very similar to the processes gone through when repainting your car and the results need to be similar to a finished automotive paint job.
14) Here, the plate has had a few spots, that had rusted, treated with a rust conversion chemical that stops any recurrence of the "disease." All scratches, and other imperfections are then filled or otherwise repaired. Any bits of bare metal are primed and the finished product sanded very smooth. Then the plate was scrubbed vigorously with a tack rag to remove every bit of dust.
15) The plate is then treated with several coats of gilding lacquer. Each coat is sanded with 400 grit sand paper and carefully scrubbed down with a tack rag again. The final coat of gold is totally free of dust and very smooth and even. No sanding is done to this final coat.
16) The next step is to put a coat of a quality clear lacquer over the gold. The gold lacquer itself tends to look too "arts and crafts" without a couple coats of clear to take the "edge" off and add depth to the finish. The clear also adds durability and the easy potential for future scratch repair that the gold lacks. Finally all the black lettering and other detail work that goes on the plate is carefully put on.
17) Here, the piano is draped with heavy pads and a heat source and circulating fan is place under the piano. A humidity gauge is placed on the sound board in order to be able to keep track of moisture as it is being driven from the sound board and shims. The reason that the sound board is dried is explained in more detail here. You can tell that the drying is finished when the cracks in the sound board show tiny indications of new wood having opened up at their ends. You don't want to dry the board so much that new cracks form or until the old cracks split open terribly. There is no reason for going that far. You simply want to make sure that the board has been reduced in size a little more than it ever could be expected to shrink in actual future usage. Then any failing glue joints are repaired and the cracks shimmed. The shims are glued into place with a wedge pressed under the sound board that pushes additional crown into the board. By doing this it becomes possible it restore crown to the shape of the board. After this process is over the piano is kept in an environment that is carefully regulated to 40% humidity to give the board the chance to come back up to the correct moisture content slowly and evenly.
18) This picture begins to give you an idea of how badly stained this board was. You see a bottle of CA glue next to one of the shims. This was one of the glues that was being used for sound board shims at that time. Now aliphatic resin and hide glue are used exclusively for this purpose.
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