>I'm not ready to accept the assertion that piano felt verdigris is a mold until >a qualified plant biologist (proper term? surely not a mycologist -- >moldologist??) is coerced into identifying the species. Patrick - I will concede that before I became a piano technician, that everything I learned about mold, mildew and other assorted furry growths came from my refrigerator, but I was referring to a specific lecture given at a convention. I believe this was presented by a piano manufacturer that had used a microscope and was showing slides of a felt bushing that had been treated for vertigris. The slides showed severe damage to the wool. The gist of the lecture was 1) vertigris was a mold, 2) that even if you killed it, it still came back, 3) it attacked the parafin used in the wool bushing. This information is crucial to how we treat vertigris. If you just use carbona, and clean the vertigris as best you can, and then repin, you are still repinning a damaged bushing and the problem can reoccur. If you rebush the flanges, the parafin may have creeped into the wood, and will reinfect the new wool bushings. What I had observed on my cedar siding was that a black, vertigris-looking stuff was growing on wood I had inadvertently treated with parafin. Although not clear in my post about my cedar siding, and I apologise for that, my concern is really about how dangerous a substance parafin is to use in pianos. Since I never observed anything growing on the parafin my grandma used in sealing her jelly jars, I am thinking that this is a wood, wool and parafin reaction. Parafin is also an ingredient in soap. Rebuilders were told to used soap to lubricate the screws that hold the pinblocks to the plate. Since then, at least one manufacturer has found that the soap leeched into the pinblock and loosened the tuning pins near these screws. In the few pinblocks I replaced, I noticed the screw holes in the old blocks were black, and often furry. I don't think we need a botanist's opinion to determine whether the green, black, pink or white stuff we find in pianos (or refrigerators) is a mold or corrosion. I don't think the black fur I find on action centers is the same thing as the black stuff on key bushings; the material is being damaged nonetheless. The circumstances that cause corrosion can be just as varied as those that cause "growths". One instance that comes to mind is that a piano manufacturer once changed their spring rail felt from red to green. Very soon they were beseiged with complaints that the hammer butt springs were breaking. Turned out that the dye used to make the felt green contained a chemical that was very corrosive to metal. >I, will, however, suggest that we don't perpetuate "theories of piano >center verdigris" without proofs better than "I seem to recall that someone...... .. and Patrick, since aeronautical engineers cannot, can you prove that bumblee bees fly? :) Carol Beigel
This PTG archive page provided courtesy of Moy Piano Service, LLC