Ron O. I'm re-reading your post and want to thank you for this technique. I can see how this would work in many situations. Sort of like the old epoxy repair for bridges where the hole is filled and the pin re-inserted. Fenton ----- Original Message ----- From: "Fenton Murray" <fmurray at cruzio.com> To: "Pianotech List" <pianotech at ptg.org> Sent: Thursday, April 20, 2006 9:54 AM Subject: Re: Was Buttr. Arch. Q for Ron N - increasing rim density > Right back at you, Ron O. > ----- Original Message ----- > From: "Overs Pianos" <sec at overspianos.com.au> > To: "Pianotech List" <pianotech at ptg.org> > Sent: Sunday, April 16, 2006 4:14 PM > Subject: Was Buttr. Arch. Q for Ron N - increasing rim density > > > > Fenton and all, > > > > At 6:57 AM -0700 16/4/06, Fenton Murray wrote: > > >How about treating the inner rim with a penetrating epoxy? > > > > Yes that would work, but you need some means of hydraulically driving > > the glue into the wood. A slightly less messy solution, which I've > > used for light density rims such as Luaun, is to drill a series of > > holes into the top face of the inner rim, spacing them about 12 mm or > > 0.5" apart around the perimeter, drilled to a depth of around 25 mm. > > The drill diameter is chosen such that the resultant holes are a > > slight press fit for maple hammer shanks (a couple of test samples in > > a piece of scrap will allow you to determine which drill size is the > > most suitable). The drill must be very sharp or it will glaze the > > surface of the hole, preventing glue from moving into the wood pores. > > For this type of work it is most important to have a series of drills > > in 0.1 mm diameter increments from which to choose. We have drill > > sizes from 1.0 to 10.00 mm in 0.1 mm steps. They can be purchased at > > quite reasonable prices in sets. One set from 1.0 - 6.0 mm, and a > > second set from 6.0 - 10.00 mm. Fill the holes right to the top with > > Titebond and drive the hammer shanks home to the bottom of the holes. > > Glue comes out of wood pores everywhere. The clean up is very easy > > compared to epoxy and the density increase overall is fantastic. A > > Japanese pull-saw can be used for trimming the excess hammer shank > > length flush with the top surface of the inner rim after gluing. > > > > If the belly rail is similarly light-weight, it can be treated in the > > same manner. Its quite an effective fix for pianos which were built > > using trash-wood for the inner rim. > > > > If you use this method, don't forget to leave the case for a couple > > of weeks to dry out before fitting the new sound board, or it will > > take ages for the piano to normalise after the rebuild. > > > > This technique, for hydraulically driving glue, can be used for > > bolstering back beam joints by drilling holes which diagonally > > intersect joints, including back beam joints with the rim/belly rail. > > Before a case is fitted with a new board all joints can be 'injected' > > using this method from above and below to make sure that the entire > > length of the joints are 'sound' (flip the case and treat the lower > > part of the joints, then set it right way up to treat the top part of > > the joints - all before fitting the sound board). Once you try this > > it will surprise you how many joints, which look to be OK, really had > > gaps all over the shop. I suspect that poor back brace joints will > > suck up energy which might otherwise be helping the sustaining > > qualities of an instrument. > > > > Look forward to meeting you in Rochester Fenton. > > > > Ron O. > > -- > > OVERS PIANOS - SYDNEY > > Grand Piano Manufacturers > > _______________________ > > > > Web http://overspianos.com.au > > mailto:ron at overspianos.com.au > > _______________________ > > > > > > >
This PTG archive page provided courtesy of Moy Piano Service, LLC