keytop glue

[harvey]

Baoli, you likely have entirely different resources and materials available
to you in China, so the following is more a primer than a specific
recommendation:

A1. PVCE = [P]oly [V]inyl [C]hlorine [E]mulsion. NOT to be confused with
pipe glue for securing plastic pipes. PVCE is chalky white in appearance,
dries clear, and has certain flex characteristics when it cures.
PVCE was introduced (not invented) initially to west coast piano
technicians by Ray McCall of Pomona, CA after his success in using it for
(cloth to wood) player work. It is water soluble/thinnable, and for this
reason, it's important to keep the container clean and tightly closed
between uses. Otherwise, one ends up trying to get 'Jello' out of a bottle.

One source for PVCE stateside:
McCall Enterprises
6187 Bellmeadow Dr
Columbus OH 43229
(614) 898-9497

A2. Not as simple. Many things have been tried, depending on the keytop
material, the thickness, and the environment surrounding the completed
project. What appears to work initially in a given situation sometimes
fails in service. Also, results vary with the _same_ product, due to
preparation and application techniques of individual users. 

Glues could be placed into family groups, regardless of brand names:

Group 1: Acetone/other solvent based. "Key cement" from piano supply
houses, "Duco cement" in tube form, "airplane glue", and so on. They work
by dissolving one or both of the materials to be joined.

Group 1a. There was an excellent keytop cement from Tuners Supply Co.
Whether it was a precursor to PVCE, or was an acetone-based product, I
don't know. Unfortunately, the company and the glue are history now.

Group 2: Latex based. "Elmers", "Wil-Hold", and others, usually called
"contact cement".

Group 3: Glue gun w/glue sticks. [Just say NO!]

Group 4: Adhesive type. Hide glue, fish glue, rubber cement, and many
others that I cannot recall. Ivory wafers could be included in this family.
Glues for the construction trade, applied by caulking guns would also come
under the adhesive category. IMO, PVCE belongs in this grouping.

Group 5. Cyanoacrylates (CA's, like Hot Stuff, Zippit, etc.) They deserve a
special category.

Group 6. To be appended by others...

Working with glues is much like working with different brands of hammers.
Most technicians find a glue or adhesive they are comfortable in using,
and, notwithstanding an occasional departure based on the recommendations
of others, remain with their choice. After learning about surface
preparation, application, cure times, and so on, the element of "surprise"
is no longer there. I know one of the first technicians who tried PVCE for
keytops. His initial response: "Never again." Now the use of PVCE for (this
application) has become popular. Perhaps this technician used too much
PVCE, perhaps his surface preparation was incorrect, I don't know. I *do*
know there's a message in here somewhere.

-jh-

At 10:47 PM 1/28/99 +0800, you wrote:
>Two simple questions:
>
>First,What is PVC-E? I know PVC is a kind of soft plastic,right? Then what
>does E mean?
>Second,If I can't get PVCE in China,Could you give me some suggestions about
>other glues for gluing on keytops?
>Thanks a lot!
>
>Baoli Liu
>Shenyang Conservatory of Music
>China


Jim Harvey, RPT
Greenwood, SC
harvey@greenwood.net
________________________
 -- someone who's been in the field too long.