unglue celluloid keytops

Posted by: Olek

unglue celluloid keytops - 11/13/12 04:21 AM

Hello,

Your best method to take out for re gluing a few celluloid key tops ? (warped by age probably/unglued)

can I uses some heat to flatten the celluloid ? (I have brass keytop presses that can be heated)

Thanks
Posted by: Chris Leslie

Re: unglue celluloid keytops - 11/13/12 12:40 PM

I have tried warming a half unstuck and already warped celluloid top. The warp just got worse and shrunk a bit. There were some wood slithers attached. That is why I now carry a couple of sets of different styles got from junk pianos where they were falling off.
Posted by: Olek

Re: unglue celluloid keytops - 11/13/12 12:51 PM

Thanks , Chris, I was afraid of that. even low heat on a press ?(a wooden block if the brass caul is too strong/hot ?)

the shrink is a bad joke ! but celluloid is so rare on the pianos here, I will not find some old keys easily. (the older materials where often "galalithe" something done with milk.

the glue may soften the material, if I use contact cement, I suppose.
Posted by: Silverwood Pianos

Re: unglue celluloid keytops - 11/13/12 01:37 PM


Celluloid will be soft and easy to manipulate when warm, but shrinks to smaller than the original size when cooled. I have had some success using strong glue and then clamping tightly in a vise.

Galalith was made from goat’s milk and the material was highly flammable almost explosive.
Posted by: Olek

Re: unglue celluloid keytops - 11/13/12 01:43 PM

Hi Dan , I just have read the story of celluloid and the birth of the first polymers... very Instructive !

The camphor is used in different quantities to produce the celluloid, and the Japanese where having most of the available camphor, hence strategies to have the trees grown in other regions... plus many amelioration's done to fight the flammable quality of the celluloid...

I am unsure contact cement is the best choice, it seem to be better with cellulose cement (the one used for airplanes models for instance)
Posted by: Silverwood Pianos

Re: unglue celluloid keytops - 11/13/12 01:47 PM


Yes Isaac, I believe the cellulose cement will melt the key top a little upon contact to improve the bonding process.

You would have to try some to see what happens.
Posted by: Supply

Re: unglue celluloid keytops - 11/13/12 04:18 PM

Quote:
Celluloid will be soft and easy to manipulate when warm, but shrinks to smaller than the original size when cooled. I have had some success using strong glue and then clamping tightly in a vise.
Galalith was made from goat’s milk and the material was highly flammable almost explosive.
It is actually celluloid which is highly flammable, while galalith is not.
Posted by: Silverwood Pianos

Re: unglue celluloid keytops - 11/13/12 08:12 PM


Yep, my mistake….going too fast and I posted it in reverse.

Galalith, made from casein and formaldehyde and is virtually non-flammable.

The word comes from the Greek words gala ( milk) and lithos (stone) hence the name milkstone or galalith.
Posted by: Olek

Re: unglue celluloid keytops - 11/14/12 07:08 PM

I noticed a very strange thing : last time I saw the keyboard, the weather was humid, the celluloid keytops where curved, and under the nail they tone unglued.

Today, they where flat, and with way less "empty tone" if any.

I suggest that they are only glued all around so the wood can swell without the celluloid crack (or they unglue only from the center.

I was expecting a lot of regluing, in the end only a tail needed some intervention, and then it was the wood below the tail that have been unglued .. (so wood on wood, no problem)