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
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