Ivory keytops

[TunerJeff@aol.com]

Dear Barrie,

    Yup, I wonder about the longevity of CA-repairs myself. It seems to be on
the brittle or frangible side of the adhesive list, doesn't it???

    Further, I question the use of any such 'brittle' or 'hard' glues for
keytop replacement. We are attempting to get a bond between the wood of the
keystick (which expands and contracts with temperature or humidity changes)
and the harder (much less flexible, anyway) ivory keytop. Using CA-Glue or
standard wood glue creates a rigid glue joint... or at least, it attempts to
do so. Problem is, the materials are too far apart in characteristics!

    As the wooden keystick 'breathes', in cycle with the ambient conditions,
it will flex. The ivory (...although not TOTALLY rigid) won't expand and
contract as much. Trapped in-between is the glue... doing it's best to keep
the two together. If one uses a rigid glue, it  WILL fail someday. Won't it?
Unless conditions around that piano are amazingly stable, that bond gets
flexed a great deal by the vicissitudes of Life! I don't use CA-glue for
keytops because I'm afraid I'll wake up one cold & rainy morning (...here in
Oregon) and find my phone ringing off-the-hook as EVERY customer who's keytop
I used it on calls to tell me the darn thing(s) fell off. Scary.

    As a student, I always wondered why they bothered to use a glue-wafer to
affix the ivory to the keys. When I asked, I was told that the
glue-impregnated cloth provided a bit of movement to the glue joint, just a
bit of 'give' in the bond between the wood and ivory. One respected
tuner/tech stated that the glue-wafer actually acted as a 'shock-absorber'
for the impact of the finger. (That might be worth a 'blind-test' at a
meeting sometime! Might be interesting to know if we could feel the
difference between the two bonding methods just by simply playing the key.
Interesting?). Certainly the glue-wafer set-up takes the factory several
extra steps in production. They could have simply used white pigment in the
glue and zapped the keys on in two easy motions... but they didn't did they?

    Isn't this why we use contact cements for adhering entire keytop sets?
Don't we need some flexibility in the equation here???

Just wondering,
Jeffrey T. Hickey, RPT
Oregon Coast Piano Services
TunerJeff @ aol.com

ps-
    Was caught by the idea of using colored tape in that interface. Mebbe
that would help add to the longevity too! (I add to mine by not eating jello,
or whatever it is...)
;>)
    Richard Wagner's Acryli-Key Repair is an epoxy that bonds extremely well
to the ivory key, and it isn't being pulled in two directions by differing
materials. Ask him about it, Barrie... but I believe he began with a dental
epoxy! That oughta bond pretty well to an ex-elephant's tusk, don't you
think???
jef