I used to heat the glue joint to align hammers, until I found out that Titebond begins to break down at about 120 degrees, and loses half its strength at about 150 degrees. I got this info from a technician named Tom Patten in his class concerning fire damage to pianos. My understanding is he got this information from Franklin, the makers of Titebond. I assume this applies to other glues as well. Maybe this isn't enough loss of strength to affect the hammer glue joint significantly, but I'd rather not take the chance. I now twist the shank, as was described in a previous response to this question. If the hammer is too far off to twist the shank, I remove the hammer and reglue with fresh glue. Sincerely, Gary Mushlin, RPT On Mar 29, 2006, at 9:16 AM, ed440 at mindspring.com wrote: > > I will second Wim's approach. > I heat the glue joint with an Ace hardware heat gun on low setting, > moving from side to side of the hammer. If correcting more than > one hammer I will move around and heat several at once. You need > to give time for the heat to penetrate to the glue, and you don't > want to make charcoal. > Then grasp the shank with shank knurling pliers just below the > hammer. No stress on the flange pinning, and very definate control. > Then reset the hammer sort of like setting a tuning pin, over and > back a few times until it's on center. > I use Titebond in my work, but have also used this method on pianos > with what-ever-it-is glue. Results seem stable, but I have not made > a research project on the question. > > Ed Sutton > > Original message > From: Wimblees at aol.com > To: caut at ptg.org > Received: 3/28/2006 2:11:50 AM > Subject: Re: [CAUT] Hammer Alignment > > In a message dated 3/27/2006 11:13:17 PM Central Standard Time, > davidlovepianos at comcast.net writes: > Do they always end up twisting in the same direction? One thought > is that > if you burn the shanks for straightening at the initial > installation and you > hold the heat gun, say, in your right hand, you might be heating > one side of > the shank more than the other which might create some unequal > tension in the > shank that might play out over the period of a few weeks or months. > I have been reading these post with interest. I seem to be getting > the impression that some of you are heating and bending the shank > to move a hammer. I personally think that might be causing the > problem Jon first mentioned. It has been my experience that the > best way to burn hammers is heat the glue joint enough to allow me > to twist the hammer. I then hold the hammer in its new position for > the glue to solidify. I have never had a hammer move after that. I > don't think the heat does any damage to the glue. I use Tightbond, > BTW. > > Wim -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/20060329/7d3f8516/attachment.html
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