Susan My CA glue failures did occur during the winter. Your post explains why. I am not up to speed on CA, and your insights have been invaluable and encouraging. I'll try your tips on some shop keys and work out a procedure. Thanks very much for your help. Paul Chick ----- Original Message ----- From: Susan Kline <sckline@home.com> To: <pianotech@ptg.org> Sent: Tuesday, September 26, 2000 9:19 AM Subject: Re: Enlightenment > At 07:19 AM 09/26/2000 -0500, you wrote: > >Susan > >I've tried CA for regluing ivory and found the joint to fail most of the > >time. I take care to clean the ivory and keystick, but usually find that > >repair has failed. I don't wet either piece with anything in the cleaning > >process, just scrape the surfaces and wipe off with a clean rag before > >applying the CA. What am I missing? > > > >Paul Chick > > Dampness, probably. You see, CA glue wants to bond and polymerize like > crazy. <grin> The only thing that keeps it liquid is an inhibitor, which > is an acid, and it's very powerful, because there is only a tiny trace > of it. It breaks down in contact with water, and it only takes a small > amount of water, such as we would have in a normally humid Oregon day. > It's possible that you tried to use it during a Minnesota winter, and > the air was just too dry. > > Try either cleaning the keystick with a damp rag, or scrape it clean, > but then smear a very thin layer of Elmer's glue on it. Put some dots > of CA glue on the ivory, spread it into a layer (quickly!) with a > screwdriver, and put it in place. If you use too much CA glue it will > squeeze out and get onto your fingers. (Heck, it'll get onto your > fingers anyway.) At that point, as you press the ivory down you'll > leave a nice vivid CA fingerprint on the ivory, which you will > then need to use acetone to remove. (I've tried scraping and 600 > sandpaper: not very effective.) Keep this squeeze-out off the fronts, > in particular, since they are usually melted by CA glue, and by > acetone as well. > > If you have a decent brand of CA glue (I like Loctite's QuikTite) > and follow this procedure, it should bond like mad, and I've never > had one come off again. Give it a try and tell us how it goes. > > Put the Elmer's on the keystick because waterbased glues can warp > ivory and because the CA won't wick into ivory. In general, if > gluing a hard and a soft surface together, put the CA on the hard > surface and the Elmer's on the porous one. If the two surfaces are > both soft (like gluing cloth to cloth) put the Elmer's on both, > squeeze together to spread it, add a small amount of CA to one > or the other, and IMMEDIATELY press together again. The Elmer's > will prevent the CA from soaking in too fast. As soon as the CA > hits the Elmer's it bonds with great enthusiasm, generating heat > and a few bubbles. That is, the squeeze-out is clotted and a little > foamy. > > Be sure your fingers are not wet with the Elmer's when handling > the CA glue. If I use CA glue alone, and stick my fingers together, > I can pull them apart, just leaving a thin layer of skin behind. > But one day when I had a trace of white glue on my fingers, the > CA glued them together so firmly that I had to go to the car to > get the acetone so that I could dissolve the bond. It took quite > a bit of acetone and a little struggling, even so, to get the > stuff to let go. > > If using CA and Elmer's to glue on rubber buttons, be sure not to > use too much, and use great care in cleaning it up. If you smear > the squeeze-out across a piano case, it'll look terrible and is > nearly impossible to remove. (Don't ask ...) > > Susan >
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