[pianotech] CA Glue

[Susan Kline]

  Mike, when I first bumbled into and later experimented with the white 
glue-CA combination, I theorized that the white glue did the heavy 
lifting for the joint long-term, but the CA bond kept the joint together 
till the white glue had a chance to cure completely.

Later, I started to wonder. It seemed that the bond was stronger with 
the CA in there, instead of just faster. As far as I know, no one has 
set out and tested this, testing bonds to destruction. It would be 
interesting if someone with real materials science education and 
experience did some lab work about this phenomenon. I'd also be 
interested in how the bond using accelerator differed from the bond 
using white glue instead, or the bond using nothing but CA.

And of course one could try these three options using different 
materials as well.

Susan Kline

On 9/9/2010 8:49 AM, Mike Spalding wrote:
> I've been using the white glue and CA method for field repairs of 
> ivory keytops since I read Susan's description here on pianotech.  My 
> "white glue" of choice for this repair is PVCE.  Can't speak to the 
> absolute strength of the bond compared to CA alone, but I like to 
> think that the flexibility of the PVCE layer will keep the joint 
> intact in spite of the differential expansion / contraction of wood 
> and ivory.  Just like installing plastic tops with PVCE, except you've 
> got a layer of CA to keep the water in the glue from curling the 
> ivory.  Bonding, while not "instant", has been fast enough, meaning 
> that after 10 seconds or so I can let go of it and the top neither 
> falls off nor curls.  Just my take.
>
> Mike