Definition, please: "Wood Flour?" Sawdust? Sanding dust? The stuff that sifts out of 80-year-old screw holes onto your face while removing keyslips? Alan R. Barnard Salem, MO -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Delwin D Fandrich Sent: Saturday, July 26, 2003 11:07 AM To: oleg-i@noos.fr; Pianotech Subject: Re: Baldwin Epoxy adherence ? ----- Original Message ----- From: "Isaac sur Noos" <oleg-i@noos.fr> To: "Pianotech" <pianotech@ptg.org> Sent: July 25, 2003 11:57 PM Subject: RE: Baldwin Epoxy adherence ? > Joe, > > I of course agree with the first part of the sentence, epoxy fills, > but when it comes to adhesion, the wetting capacities of epoxy looks > poor to me, so the bond is more mechanical than structural. > > I like to hear what others have to say about those resins as glue (I > know there are some specific compound for epoxy glues) Most of us who use epoxy regularly use products designed for wooden boatbuilding. It is expressly designed to work well with wood. True, these epoxies do not have as much bonding power as other woodworking adhesives when both are used under ideal conditions. However, in repairs such as loose bridges it is often impossible to get a perfect wood-to-wood fit without completely disassembling the piano. This means that their is going to be a slight gap between the two adherends. There is no other commonly available woodworking adhesive that has good gap-filling characteristics besides epoxy. It is our practice to use traditional woodworking adhesives whenever possible and/or practical. In those situations where a gap may exist between two components we use epoxy (either straight or, most often, with a wood flour filler). > > Did some meet failed epoxy glue joints in this domain ? gluing back > post and wrest plank ? We do use epoxy while gluing in the belly braces we add to grand pianos. We also use a filled epoxy to accomplish the final bedding on pinblocks and, sometimes, while gluing them into the rim. I've not known of either to fail. None of these are applications in which the joint will be under high stress loads. One thing to keep in mind--epoxy does exhibit a fairly high amount of creep under long-term stress. Our shop has seen a broad assortment of loose bellybraces that have been glued by other means and other adhesives, however. Epoxy, because it penetrates endgrain well and because it is a good gap-filler is the only adhesive that makes a reasonably good butt joint bond. > > One thing I experimented myself with epoxies is the immediate (one > good exposure only) rise of an hyper sensibilization, and now, > whenever I file, sand or work on epoxy that is may be not totally > cured, my hands are itching and get red (I feel they are ready to grow > if I insist). > > Wear mask and gloves (I had mask only), it is very annoying as the > same reaction occur with polyester repairs also. Yes. Just like the directions and warning labels all say--protect your skin. At the least use one of the readilly available protective skin creams. Different people react differently to these products. Some can get by with using them for years with no problems at all. Others, after becoming sensitized, can not be in the same room with uncured epoxy resins. So far, I've been lucky but this is one of the biggest drawbacks to using epoxy. That, and it's very messy stuff to work with. Del _______________________________________________ pianotech list info: https://www.moypiano.com/resources/#archives --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.495 / Virus Database: 294 - Release Date: 6/30/2003 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.495 / Virus Database: 294 - Release Date: 6/30/2003
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