<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Early Asian pianos</title></head><body> <div><font face="Arial" size="-1">Glenn, Andrew and other list lurkers,</font></div> <div><font face="Arial" size="-1"><br></font></div> <div><font face="Arial" size="-1">In a message dated 6/21/2001 9:32:02 AM Central Daylight Time,</font></div> <div><font face="Arial" size="-1">glenn@graftonpiano.com writes:</font></div> <div><font face="Arial" size="-1"><br></font></div> <div><font face="Arial" size="-1"><br></font></div> <blockquote type="cite" cite><font face="Arial" size="-1">. . . .The underlying reason why the polyester cracked</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">is because they did not use a resin surfacer sheet on top of the</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">wood. Yamaha does and as a result this type of damage is almost</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">unheard of on a Yamaha. We have seen it on other pianos, including</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Boston pianos which lack the resin surfacer sheet.</font></blockquote> <div><br></div> <div>But have a polyester film which is too thick.</div> <div><font face="Arial" size="-1"><br></font></div> <div><font face="Arial" size="-1">Andrew Remillard responded;</font></div> <div><font face="Arial" size="-1"><br></font></div> <blockquote type="cite" cite><font face="Arial" size="-1">Thank-you for pointing this out.  I have seen this problem on a number of</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Asian pianos and 1960s European pianos and never new the cause other than the</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">wood moving underneath the finish.</font></blockquote> <div><br></div> <div>Its is also related the normal temperature gradients the piano is subjected to when combined with a polyester film which gets stressed if its too thick, on account of the temperature variation between the surface of the film and the inner body of the thick film. When this situation occurs, a process not dissimilar to the exfoliation of rocks causes the film to either crack, or to delaminate completely.</div> <div><br></div> <blockquote type="cite" cite><font face="Arial" size="-1">I have seen it on an early Kawai, but</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">your right, I cannot remember seeing it on a Yamaha.  </font></blockquote> <div><br></div> <div><font face="Arial" size="-1"><br></font></div> <div>One of the main reasons why Yamaha polyester tends to remain on the piano, as opposed 'on the floor' in sheets, is that they tend to stick to their maximum recommended polyester film thickness (0.6 mm). The resin surfacer which Glenn referred to is more for the purpose of preventing the wood grain from showing through the polyester film. Many manufacturers have problems with cracked polyester because the film thickness is too thick. They do this to in an attempt to reduce sand throughs, but it can create a long term disaster.</div> <div><br></div> <div>Regarding stripping the old polyester, a heat gun and a good scraper will get it off in a very short time.</div> <div><br></div> <div>Regards to all.</div> <div><br></div> <div>Ron O.</div> <div><br></div> <div>PS. Thankfully, our piano's nearly ready. Might be able to get an overhead image up on our site soon (I'll let the list know when, where and if). The photo shoot was a couple of days ago.</div> <div>-- <br> ______________________________<br> <br> Website:  http://www.overspianos.com.au<br> Email:        mailto:ron@overspianos.com.au<br> ______________________________</div> </body> </html>