<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2900.2802" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT face=Arial size=2><EM>"What would be wrong with preemptively treating all the bridge pins in the whole piano with CA..."</EM></FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial>I'm not sure how much effect CA will have on a fully assembled newer piano in excellent condition - remember CA has little shear strength - but I think the general idea is a good one. This is why myself, and some others at least, epoxy-treat the bridge pin hole during the pinning procedure of rebuilding. There are different ways to do it, but I swab the bridge pin hole with a length of piano wire dipped in epoxy (I get a couple drops in there). Then I dip the base of the new bridge pin in epoxy and tap it in place.</FONT></DIV> <DIV><FONT face=Arial></FONT> </DIV> <DIV><FONT face=Arial>Terry Farrell</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2>----- Original Message ----- </FONT></DIV> <DIV><FONT face=Arial size=2>> Speaking of CA to fill the gaps around bridge pins, let me make a few <BR>> suppositions, then advance a thought.<BR>> <BR>> 1. Besides filling the gap, the CA also penetrates the wood surrounding <BR>> the hole, and then solidifies into a sleeve which is custom-fit to the <BR>> pin and its particular hole. So, to the extent the CA adheres to the <BR>> pin, it not only corrects the fit, it also locks it into the bridge cap <BR>> and root.<BR>> <BR>> 2. Presumably, the CA we choose to use is as rigid as wood or more so, <BR>> and therefore would conduct vibration as well or better (is this true?).<BR>> <BR>> 3. Because it is a type of plastic, the CA'd bridge resists <BR>> humidity-cycle-related dimensional changes better than naked wood would.<BR>> <BR>> 4. Therefore, besides filling gaps, it seems to me that CA _possibly_ <BR>> improves the bridge and cap functionally, above and beyond just <BR>> repairing looseness.<BR>> <BR>> So this all makes me wonder: What would be wrong with preemptively <BR>> treating all the bridge pins in the whole piano with CA, before there is <BR>> ever a problem, to prevent the development of loose bridge pins and <BR>> related possible falseness, tuning instability, and ugly cracking? The <BR>> penetration of the glue into the surrounding wood spreads the <BR>> side-bearing load into a larger mass, thus reducing ovalling and <BR>> improving both dimensional and therefore tuning stability. The enhanced <BR>> stability might prevent cracking at the notches from ever getting <BR>> started, thus preserving both tone and appearance.<BR>> <BR>> Has anyone noticed any kind of drawback to the use of CA, especially <BR>> tonal, or is its effect always somewhere between zero and positive?<BR>> <BR>> Inquiringly,<BR>> <BR>> -Mark Schecter<BR>> Oakland, CA<BR>> <BR>> <BR>> John Formsma wrote:<BR>> ><BR>> > What besides filling gaps would CA do? It wouldn't add mass.<BR>> ><BR>></FONT></DIV></BODY></HTML>