This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Comments below: =20 > Terry Farrell wrote >=20 > > >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 > > >=20 > 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. =20 > > Ron Nossaman wrote: >=20 > > 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. >=20 > 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. >=20 > 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.=20 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. >=20 > 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. >=20 > > > > 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 >=20 > 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. >=20 > Cheers > RicB ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/f7/49/12/47/attachment.htm ---------------------- multipart/alternative attachment--
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