Someone wrote: <<I noticed a yellow powder residue distributed over the action.... from a dry chemical fire extinguisher .... the action is a bit sluggish.... presence of residual yellow powder combined with the lubricant make matters worse? I have not experienced this, but the chemical you are describing is Mono Ammonium Phosphate, and is very corrosive. It is used in multipurpose fire extinguishers, for A,B, C, etc. fires. There is also another material in with it that reacts to the heat in a fire and produces another set of chemical reactions. I would suggest that you blow the action out very well with compressed air, then you might go a step further. Since most technicians used to treat sluggish centers with water and alcohol ( it works), before the Protek bandwagon came to town, I think that I would remove the action and liberally wash it off with water. Almost hose it off, avoiding leathers and felts - those should be blown off first with compressed air. The centers will get wet, swell and freeze for a time before it dries out, but the corrosive chemicals should then be almost gone. Then the centers should be free, as though you treated them with water and alcohol. The yellow powder does not dissolve well in water, but experiment with some cheap solvents that you can but for $3.00 per gallon. Try mineral spirits, acetone, etc.- and perhaps these can dissolve the residue. If the piano has been sitting for a long time, the corrosive effects may be already at work. Pull a few centerpins and examine under magnification. You do not have to go "all or nothing". Try putting water in a hair spritz bottle, add a little alcohol or acetone to reduce surface tension, and try it on a section of perhaps 5 notes. Then let it dry out and see what happens. If you try this, let me know what the results are. Bill Simon Phoenix
This PTG archive page provided courtesy of Moy Piano Service, LLC