This is explosive territory, so I'll say what I do without commenting directly on others' methods. Over the years I've used just about every product and method and seen the results, after years, of the products and methods used by other restorers. One excellent restorer I know always uses a high quality yacht varnish (spar?) and swears by it, but I've never actually compared tonal results "before and after" of his pianos and have never followed his practice. For several years now I have used the same method on every piano. My aim is to get a hard mirror finish as thin as possible on the board. I do not aim at any significant absorption of the finish into the wood and seek only excellent adhesion to the surface. Everything I've ever read suggests that the finish on a soundboard is mainly protective and cosmetic. It seems to me logical to think that hardness and smoothness will also affect the radiation of sound from the board, and though I have no scientific evidence that this is so, I work on the principle that it can do no harm to presume that it is so. I begin work on the soundboard as early as possible in the resoration, because it requires a lot of labour and also a lot of time, even when spirit-based products are used. All the pianos I work on will have been finished with a spirit-based varnish or lacquer, normally a solution of various resins and gums, which is superficial and can quite easily be scraped off. For this I use a collection of very old and very short broad chisels, specially adapted for the work. Once all the superficial varnish has been removed, I remove the remainder with P150 Fre-cut and finer. In between I will wipe the board along the grain with a rag soaked in spirit, mainly to show up where varnish remains. Next I damp the surface with water and paper up again when dry. This process may be repeated several times. All the while I am careful not to reduce the thickness of the board by over-zealous papering up. Once the board is visually as even-coloured as possible I will do any shimming that is needed. I won't go into detail about this, since it is a topic on its own. SInce I use hide glue and a lot of moisture is involved, I will leave the shims proud for several days before trimming level and papering up. I next give the board a coat of hot weak size made from rabbitskin glue, and when this is dry just lightly skim over the board with paper to remove any roughness. The polish I use for the soundboard is not quite the same as I use for the case and contains additives that give a harder and less permeable finish. Basically it is "special pale" shellac polish and just what my supplier adds, I'm not sure. I brush this on with the grain, usually two coats at a time. After each application, I leave the surface to go good and hard and then cut down with P240 Fre-cut, used dry after the first application but used wet (yes! but it must be MMM) after subsequent coats. I do not aim to build a thick body but only to achieve a flat finish without the peaks and valleys of the winter growth and summer growth. Once I have this, I begin to work with the French-polishing rubber, but mainly in straight lines and without the use of oil. This may continue over a period of days or even weeks while the polish hardens thoroughly and sinks. For the final finish, I use standard French-polishing finishing-out techniques, working with oil at first and using the normal circular and figure-of-8 motion. I let days pass in between and continue until the finish is to my liking. Though the time from start to finish may be weeks, the time taken in actually getting the finish is only a few hours when added up; each coat with the brush will take only 5 or ten minutes and the rubbers sya 20 minutes each. Most of the labour is in the preparation of the wood in the white and most of the time is just waiting for things to dry and harden off. A final burnishing with a gentle reviver can do no harm but is unnecessary if the spiriting off has been done carefully. JD
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