> Date: Thu, 01 May 1997 10:05:07 -0400 (EDT) > From: JIMRPT@aol.com > Subject: Re: Glue collars > To: pianotech@byu.edu > Reply-to: pianotech@byu.edu Jim, I agree. I have a number of Kawai uprights that had nice glue collars but were clicking like crazy when the glue joint failed. The problem was no way for the glue to escape via a hole in the hammer or groove on the shank. > Fred; > I agree with you on the overrating of glue collars in judging the quality > of a hammer glue joint. A glue collar can indicate several things among them > being: > 1. An extremely close fit of bore hole and hammer shank. In this instance > the moulding scrapes off the glue as it is being positioned on the shank, > leaving very little glue inside the moulding for bonding to the shank. > 2. Glue that is too thick, or cold, for the intended purpose whose viscosity > allows it to 'roll' up the shank as the hammer is positioned. Again leaving > very little glue in the moulding for bonding to the shank. > I believe that it is better for a bore hole to be a 'little' too large > thereby accommodating a good glue bond, rather than being a 'little' too > tight thereby not accommodating a good glue bond. There are exceptions and > different techniques that address the hammer hanging process, as pertains to > glue joints, and a good, neat, small glue collar is just one indicator of a > good glue joint but it doesn't follow that if there is a good collar that > there is a good joint. > One repair method for the original problem voiced, that started this > thread, of loose heads is to use CA glue in the very thin formulation. I > don't necessarily recommend it but the method will work well as an expedient > repair.. The old glue collars need not be removed, and in fact might > facilitate the bonding with the CA. > The thin viscosity will allow the CA to migrate into the loose joints and > bond the moulding and shank, eliminating all clicking noises. > Just some thoughts. > Jim Bryant (FL) > > ilvey Pacifica, CA ilvey@a.crl.com
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