----- Original Message ----- From: "Farrell" <mfarrel2@tampabay.rr.com> To: <pianotech@ptg.org> Sent: January 08, 2001 1:06 PM Subject: Re: Shimming - was: Was it something I said? > OK, a theoretical problem. If the new "stronger" shim causes the adjacent > "damaged/crushed/old" soundboard wood to develope cracks along the new > shim, wouldn't epoxy do the same thing? No, it doesn't. > Certainly the epoxy isn't going to squish much. Yes, it does. At least it does if you've used the right type of epoxy. Marine-grade epoxy -- WEST, System Three, etc. -- has quite a lot of flex unless you add fillers that stiffen it. Colodial silica being one of the worst offenders. But if you use just a bit of wood flour and fresco colors it will remain slightly flexible. In the winter you can feel a very slight dip in the surface and in the summer you will find just a bit of a hump. But no new cracks. Year after year after year. > Or do you somehow let thin epoxy soak into the adjacent old board > material and then put a thickened mixture into the crack. Yes, you do that too. > Also, when doing > an epoxy "shim", is there any reason to rout out the crack? Or do you just > fill it as is? No. There is no reason to rout out the crack. Just fill it as is. Make sure the board is glued down to the ribs first. Sometimes you might want to clean out a crack if it has accumulated enough industrial pollution to make it really black and ugly. Del
This PTG archive page provided courtesy of Moy Piano Service, LLC