CA Glue

[Susan Kline]

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At 09:27 AM 8/18/2005 -0500, you wrote:

>Susan:  The Elmer's could be interfering with the cyanoacrylate 
>polymerization in a good way.  (Sorry, sometimes I get carried away and 
>forget that not everyone uses "normal" words the same way we chemists 
>do!)  I think Elmer's is from an organic source (still horses?) which the 
>CA would "stick" to, and could make the bond stronger than a homogenous CA 
>polymer due to increased branching and interlocking of the molecules.  My 
>question (perhaps because I have as yet zero experience with CA in piano 
>applications) is "Why do you need a "super-glue" accelerator?"  Every time 
>I've used it, it bonds very quickly on it's own.
>
>John Delmore


Well, John, I do use straight CA for some things. The problem is that with 
cloth and leather, it wicks in too easily, and cures up to be very hard. 
Sometimes, in dry weather especially, it is shy about setting up at all, 
especially if one uses too much. With wooden parts, it also depends on a 
very good fit, not being a gapfiller except in the gel-types. White glue is 
a lot more forgiving, more flexible once set up, and when the two of them 
do their excited little dance, they don't wick into cloth or leather as 
far, especially if you don't use too much of the CA. If I don't put the CA 
directly into a spread-out patch of white glue, I put the white glue on the 
more absorbent surface (cloth or leather), and the CA on the harder 
substance, like wood, because it won't wick in as far as into the cloth.

By using both glues, you can use a lot less CA. Actually, I started out 
using the CA to "kick" the white glue. It was the white glue I wanted to 
use, but it took too long to set up. Later on I realized that it worked the 
opposite way, with the white glue as the kicker. Still, what does it matter 
which is kicking which? One ends up the same place after 1/2 hour, when the 
white glue would have set up anyway.

I like that idea of branching and interlocking polymers because of the 
organic nature of the Elmer's. I thought they made Elmer's from milk 
protein? Elsie the cow used to be on the label? I wonder if they still do. 
I haven't tested the pH of Elmer's but I wouldn't be too surprised to find 
out it was a mild base.

You wouldn't just happen to have a way to test the pH of Elmer's, would 
you? <grin>

The glue trick also works with Titebond, but I use Elmer's so much of the 
time I don't know if the bond is different with the yellow glues. I just 
know it seems to be excellent with Elmer's.

Years ago, I heard on the car radio that the guy (not named Elmer) who 
invented Elmer's Glue had died. I gave him a moment of silence, as a 
tribute. That is one fantastic glue!

Susan  
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