[pianotech] Epoxy

[Ron Nossaman]

On 11/5/2012 8:22 PM, Dean May wrote:

> If epoxy penetrates cracks just as well as CA does, then why don't we use it
> to treat loose tuning pins?

I'm going to assume you want a real answer.

CA doesn't need mixing, it penetrates QUICKLY where epoxy does not, as 
I've already said, and it cures quickly. There is no requirement 
whatsoever for strength, as there's no tension involved. You're merely 
making a less compressible fiber reinforced plastic. This all makes CA 
an ideal choice for this application.

Epoxy, while it will eventually penetrate the crack, is difficult to 
keep over the crack. It tends to spread more. While it has considerably 
more strength than CA, that strength isn't necessary in this case. It 
requires mixing, and takes considerably more time to penetrate unless 
heated. This makes it impractical for this application.

This does not mean that CA is a good choice for structural cracks, nor 
does it mean that epoxy doesn't penetrate as far as CA, given time and 
containment. Neither is universally applicable to all situations, but 
both have attributes that make each a good choice for some specific 
uses. This is the case with any glue, and choosing a glue for a specific 
use requires taking more than one superficial attribute into account.

Ron N