WHere's Waldo

[Farrell]

Hey Don,

I use CA glue quite a bit, but typically on non-stress applications. I do
not consider myself any expert on the physical characteristics or dynamics
of CA glue.

But I have used a variety of adhesives. My comments below are based on my
experience with epoxy - and I'm thinking that CA would follow suit - please
correct me if I am wrong.

You recommend using the thin CA to coat the crack and then using an
accelerator to cure the CA. Then you recommend using thick CA to fill the
crack. What kind of bond is formed between the cured thin CA and the thick
CA? Thinking along the epoxy line, the thick CA should be applied before the
thin CA cures - that way all will bond into a single unit - the gap-filling
thick stuff, and the stuff that soaked into the walls of the crack.

I'm speculating that CA might be like epoxy in that a chemical bond (formed
before cure) will be a strong bond. But if the initial thin CA application
is allowed to cure - and the surface is not coarse-sanded for adhesion - and
the thick stuff is applied, you may not get a good bond - and we are talking
about a tension stress here.

Just a thought.

Terry Farrell

----- Original Message ----- 
From: "Don" <pianotuna@accesscomm.ca>
To: "Pianotech" <pianotech@ptg.org>
Sent: Thursday, September 02, 2004 11:20 AM
Subject: Re: [Files] WHere's Waldo (was Big hammers) (Modified
byKentSwafford)


> Hi Jason,
>
> Epoxy it to prevent the crack spreading. Or if you don't wish to epoxy use
> CA glue. I would make full disclosure to the client that the repair is
just
> a preventative and in no way increases the value of the instrument.
>
> If you choose CA glue:
>
> 1. coat the crack with water thin CA glue
> 2. consider using an accelerator--or just breath on it for five minutes
> 3. fill the crack with thick CA glue
> 4. start tuning the piano, after the temperament is done
> 5. check the crack and add more thick CA glue
> 6. continue tuning the piano and adding CA glue until no more is needed.
> 7. present a bill for services rendered.
>
> At 10:48 AM 02/09/2004 -0700, you wrote:
> >Here's the low end of the bass bridge, out of focus but you can see how
> >badly cracked it is. Should this be fixed, or band-aided, or left alone?
The
> >piano IS tunable.
>
> Regards,
> Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.
>
> mailto:pianotuna@accesscomm.ca http://us.geocities.com/drpt1948/
>
> 3004 Grant Rd.
> REGINA, SK
> S4S 5G7
> 306-352-3620 or 1-888-29t-uner
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>