My thoughts exactly. Al From: David Love Sent: Monday, October 19, 2009 4:46 PM To: pianotech at ptg.org Subject: Re: [pianotech] U1 - stained bass strings I don't think it's from moisture or atmospheric contamination. It's some contaminant that probably occurred in the handling of the strings in the factory or during the making of the strings themselves with the copper wrap. I doubt it will effect string wear or breakage (or tone). However, putting alcohol on there certainly can. If it really bothers the owner call the dealer and tell them, maybe it's a warranty item. Other than that, leave it alone, you can only make it worse. David Love www.davidlovepianos.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Rob Mitchell Sent: Monday, October 19, 2009 11:32 AM To: pianotech at ptg.org Subject: [pianotech] U1 - stained bass strings I've been working with Yamaha on this, but the best we've come up with is that some sort of atmospheric contaminant is attacking the strings. Thought I would try this group to see if anyone has seen the problem. This is on a 4 year old Yamaha U1. As you can (hopefully) see from the pictures, this is a very unusual phenomena. It looks to be some kind of ink or marker in some very odd places. It occurs on ALL the wound bass strings under the damper felts and at the hammer strike points. For the damper felts, the stain is exactly at the contact point between the felts and strings. For the monochords, the stain wraps around the string. For the bi-chords, the stain is between the strings from the wedge. It's as if someone used ink-soaked dampers and hammers to check for damper contact and strike point. (The hammers and dampers themselves on this piano are normal and show no signs of the stain). The stain is not just on the surface of the coils -- it seems to be all the way into the grooves. Furthermore, both the L and R strings on B1 (as well as some other strings) have the markings smeared from the dampers almost up to the tuning pins. And there is an every-fourth-string marking again closer to the tuning pins. All the strings look completely normal and free of the markings below the dampers. I tried some fine emery paper on a B1 string and the marks seemed to scrape off fairly easily. I didn't want to try anything more aggressive like alcohol, wire brushing or steel wool. The customer's concern is that at a minimum, this diminishes the resale value of her piano and at worst, might be something that would accelerate string wear/breakage. Anyone seen this before? Rob Mitchell Piano Service (415) 994-1030 www.mitchellpianoservice.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20091019/2d9c7267/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC