My old mentor was extremely eccentric, but back in the 70's he knew someone at the factory who he had the odd phone conversation with when he had a pressing question. He always insisted that the factory literally dipped pinned centers in a combination of mutton tallow and paraffin in those years, and this was the direct cause of verdigris. This would explain why it comes bubbling up out of the wood given enough heat--even at a point on the hammer flange farthest away from the actual center. Greg Granoff Humboldt State University ----- Original Message ----- From: "Fred Sturm" <fssturm at unm.edu> To: "College & University Technicians" <caut at ptg.org> Sent: Monday, January 3, 2011 3:13:06 PM GMT -08:00 US/Canada Pacific Subject: Re: [CAUT] Humidity Damage On Jan 3, 2011, at 2:55 PM, Ed Sutton wrote: More precisely, I almost always find piano verdigris in old Steinway parts which were apparently treated by impregnation with paraffin or some kind of oil, presumably to make the parts resistant to humidity. I have also seen it in old Mason & Hamlin wippens, though not to the extent it occurs in old Steinway parts. This would supoort Susan Graham's comments about paraffin treated action parts causing verdigris. Is there reliable evidence that paraffin was used by Steinway? I have always thought they used some kind of organic grease/oil, probably of animal extraction (mutton tallow being one candidate). Organic oils tend to get sticky over time, like linseed oil but true of other organic oils as well over a longer period. I don't think paraffin does so, though I could be wrong. Maybe there is paraffin that is less refined that could lead to problems. I have also thought the green color was leached from copper in the centerpins, and was more of a visual clue than an actual part of the problem. (I have an oiler I keep Protek CLP in. It has a brass spout, and the Protek gets green over time. I notice no problem with the Protek, and no sign of deterioration of the spout). I don't guess anybody has ever bothered to do a chemical analysis of the offending bushings? Nah, that would actually lead somewhere <G>. Regards, Fred Sturm fssturm at unm.edu http://www.youtube.com/fredsturm
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