Hot hide glue with a little Show White (Titanium Dioxide) mixed in. Clamp with heated plates, let dry overnight.

I've had excellent longevity with CA for gluing keytops with the Loctite water thin brand, which comes in 1 or 2 oz. bottles. It has a very thin spout which can apply the glue where I want it. There's a small needle in the cap which helps a little to keep the spout from clogging up.

My procedure: prepare both surfaces until there is an excellent dry fit and no dark dirt is left to show through. If the original wafer is still there, it can be cleaned with a barely damp towel to lighten it, since a small amount of moisture helps CA to set. If the wafer is already gone and the key is dark, I sometimes use white-out (left to dry) in place of titanium dioxide in the glue. One would think that it might weaken the glue joint, but it usually seems to work all right.

Now, my "glue trick" moment: one I have a good fit, with the seam edges very clean, and the level good across the seam, I take a drop or two of white glue and spread it evenly onto the key (NOT the ivory, which warps when exposed to water.) Just barely damp and tacky is right. Then I turn over the cleaned ivory (all glue or dirt scraped and sanded off the back) and I put a number of dots of CA onto the back side of the ivory, making sure there are plenty near the corners.

I used to put the dots on and spread them into a thin sheet using a screwdriver, but I've found that sometimes the glue starts to set too much before it meets the keytop this way. The dots will stay liquid and give me a little bit more working time, since the parts which aren't exposed to the humidity in the air stay liquid. It is still important to get the ivory exactly the right place very quickly. If some of the glue squeezes out and gets on your fingers, be sure to clean it off before pressing the ivory into the keystick, since it is hard to remove from the top surface. With plastic keytop, it's impossible.

Bonding is near instantaneous, and if the glue is reasonably fresh and the surfaces are good and the ivory isn't warped to begin with, I've found longevity of the bond is excellent. Well, they just don't come back off.

Roger --

I'm glad to know I'm not the only person observing these things.

I can think of a few other reasons people might fail with CA on ivory, though old or inferior glue certainly would qualify. For general use of CA, it won't set up properly without a kicker in very dry climates. Well, the thin smear of white glue IS a kicker.

Second, they could experience what I did a few times. I used CA which was getting a little old in my kit, and I spread a thin sheet of it onto the back of the ivory, and by the time it got to the keystick it had already set too much.

If people were using it and managed to stick their fingers to themselves, or if they managed to mar plastic keytops by having some on their fingers while they pressed, they could certainly be discouraging, as could getting the ivory on crooked and having trouble regluing it. Actually, I've found I can carefully pry a newly-glued ivory back off with the edge of a knife for a little while. The bond seems to strengthen after awhile.

I used to be able to get the Loctite water thin CA in almost any hardware or variety store. Then it started to disappear. I can still find it at the local BiMart. I bought several bottles there a few times, hoping it would encourage them to continue to carry it. Nothing like finding an empty hook when restocking ...

Susan

Susan,

Also, I'm currently installing a new set of hammers using Wessell Nickel & Gross shanks with Loctite CA glue that has an expiration date of 7-11-17. If CA was unreliable, as others have suggested, WNG is in big trouble. Can you imagine the glue failures the industry would experience in a couple of years? 

Mark, I seldom have occasion to glue on plastic keytops, but the white glue/CA did work for it. My friend Donnie Byrd took a trip to Cuba and installed a whole set of plastic keytops on an old upright using the two glues. Then she went back a year later, found the piano in a school, and checked the keytops, which were still glued down all right.

The white glue is the kicker, and the CA will dissolve its way into plastic keytop, just like acetone will dissolve a keytop for a (in my opinion very POOR) voicing solution. So adhesion of the CA to the plastic seems to work all right. The worst problem is that any spilled on the top side will permanently mar the surface, as it will also mar a formica counter top. (Don't ask me how I know ...)

I suppose medium viscosity might work, but I keep the water thin with me because it is so good for loose tuning pins. What kind of life do you find the medium viscosity having once the bottle has been opened? To my surprise, I can often get months out of one of the little water-thin Loctite bottles.  I make sure that the lid goes back on immediately after I've used it, and of course I keep it in a ziploc bag. 

Thanks for the information about the medium viscosity CA, Mark. It's true that it might not wander to places it shouldn't be quite as readily.

The main key to goof-proof ivory gluing, in my opinion, is to learn how much CA is the right amount. Put on too much, and it will squeeze out, all over one's fingers, from which it can migrate elsewhere. If some ends up on the top of an ivory, it can be removed with acetone, but acetone melts plastic key tops.

I have had success using a combination of CA glue to the ivory surface with Titebond 'Molding & Trim' glue on the wood key. This provides quick and permanent adhesion without risk of warping the ivory keytops. The moisture in the PVA glue accelerates the CA glue so working time is limited.

- scrape / clean wood key surface

- apply as necessary white Killz primer [very sparingly] to whiten the wooden key surface.

- spread thin layer of CA glue on back of keytop, with thin layer of Titebond to the primed wood. Align, press firmly together and hold for a minute and you are done.  

Roger,

How do you know when you've "flooded" it?

Do you think that the diminished sustain caused by flooding is due to glue on the speaking length of the string? Or because the string is glued to the bridge pin, and therefore it's movement is impeded? Or ???

Thanks,

Alan