No. Drill, swab with epoxy, drive pin. Terry Farrell ----- Original Message ----- From: "gordon stelter" <lclgcnp@yahoo.com> To: "Pianotech" <pianotech@ptg.org> Sent: Friday, May 23, 2003 10:49 AM Subject: Re: Bridge Pin Height Regulation, was: More, More (was Re:TharShe Blows!) > Drill, impregnate with thin epoxy, drill again and > drive pins? > Thump > --- Farrell <mfarrel2@tampabay.rr.com> wrote: > > Comments below: > > > > > Terry Farrell wrote > > > > > > > >Arrrggggg! I have done that same technique on > > an old bridge as part of > > > > >refurbishing the bridge. I'd be afraid to do > > that on a new bridge. I > > > > >suspect there is always some resonable concern > > regarding how much epoxy is > > > > >absorbed into the wood and out of the void > > between pin and wood before the > > > > >epoxy hardens. My plan is to swab the hole with > > unthickened West System > > > > >epoxy and drive the pin into a normal tight > > hole. > > > > > > > > > >Terry Farrell > > > > > > > > Why would a (very) little epoxy absorbing into the > > wood be a problem ? > > > > If the bridge pin is only a tad smaller than the > > hole, there will only be a small volume of epoxy > > filling any void space between pin and wood. If the > > wood absorbs the epoxy, then there will be none or > > little epoxy filling the void by the time it cures. > > Just a concern. > > > > > > Ron Nossaman wrote: > > > > > > > I suppose it depends on what you think you want. > > If you think you want the > > > > pin bottomed in the hole, you can't use epoxy > > unless you arrange an escape > > > > route for the excess that will prevent the pin > > from bottoming - or blowing > > > > out somewhere else from hydraulic pressure as > > you drive it to full depth. > > > > That's going to be either an oversize hole, or > > drive it dry. If you think > > > > it isn't necessary for the pin to bottom in the > > hole, the epoxy can escape > > > > into the excess depth of the hole without making > > the hole oversize or > > > > blowing out elsewhere, or you can drive it dry. > > the one thing you can't do > > > > with an oversize hole is drive it dry, bottomed > > or not, and expect it to be > > > > functional. > > > > > > This is all true enough as far as it goes. I do > > use essentially oversized holes... > > > that is to say if the pinis just slim enough that > > it can be pushed in and taken > > > out dry with the fingers, then the holes are > > obviously oversized. The (very thin) > > > epoxy can find its way up the sides of the pin to > > form and allowed to form a > > > collar at the top. Clean off as necessary. > > Judicious use relative to the amount of > > > epoxy put into the whole limits overflow / waist. > > One little trick that takes care > > > of this and any bleed off into neighboring holes > > is to use a piece of piano wire > > > to gauge how deep the hole is... which tells you > > how much epoxy you need to drip > > > in. Pins being of the same length then will then > > end up << bottomed out >> in the > > > epoxy and will be one hundred percent solidly > > coupled to the bridge on all > > > surfaces. Cant hurt me thinks. > > > > > > As will every thing... practice makes perfect and > > you get the hang of how to > > > accomplish this one successfully fairly easy. But > > what I like most is the long > > > term. Seems to stay solid for like ever. > > > > Another thing to keep in mind with epoxy - it relies > > on a mechanical bond between wood and epoxy and > > between metal and epoxy. It is recommended by West > > System that when bonding with epoxy to metal that > > the metal surface be sanded rough, coated with thin > > epoxy, and the epoxy sanded into the metal for the > > most secure bond. A nice new shiny bridge pin is not > > likely to establish a good bond to epoxy. I can chip > > epoxy off any glossy surface real easy when I get > > waste on it - my floor, table top, etc. > > > > Terry Farrell > > > > > Getting a pin into an undersized hole > > > without damaging the wood in one way or another is > > a good trick, and one that it > > > would seem to me easily takes as much time and > > carefullness as dealing with the > > > kinds of problems the epoxy solution presents. > > > > > > When so many types of falsness are so easily > > curred by CA treaments, or epoxy > > > treatments, it seems to me like a good idea to > > begin this way. Especially when the > > > end result seems to last quite a bit longer. > > > > > > > > > > > So it seems to me that the first thing you need > > to decide is if you want > > > > the pin bottomed in the hole or not. > > > > > > > > Ron N > > > > > > This way you dont have to make that decision, tho > > the pin ends up bottomed out in > > > the epoxy. I'd like to know what this concern > > about the epoxy soaking into the > > > wood is all about tho. > > > > > > Cheers > > > RicB > > > > > > > __________________________________ > Do you Yahoo!? > The New Yahoo! Search - Faster. Easier. Bingo. > http://search.yahoo.com > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives
This PTG archive page provided courtesy of Moy Piano Service, LLC