How does CA cure?

[Roger Jolly]

Hi Susan,
               
>Do you remove the grand action? Or is it enough to put something like a 
>folded newspaper between the bottom of the pinblock and the action? Do you 
>find that the CA drips through?

Yes I remove the action, I also use electricians PVC tape to tape the
bottom of the holes if they are bored straight through. The 5 min it takes
to slide the action out gives one heck of a safety factor. The thin CA can
sure run where you don't want it. Don't ask, I may turn red. <g>

>
>>There is enough evidence to convince me the CA glue is stronger if left to
>>it's own good time to cure.
>
>I'm glad to hear this. On the other hand, my "glue trick", which kicks the 
>CA with white glue or Titebond, seems to end up strong enough, in fact, 
>sometimes it seems stronger than either glue alone. 

You have made me a convert, but in this case we are after wicking and
capillary attraction to get the job done, white glue would inhibit this.

I have a model for why 
>this might be, but no idea whether it is accurate or not. When the CA glue 
>mixes with the wet glue, it seems to froth and expand a little, as well as 
>heating up. If the parts are held strongly in contact, I think that the 
>foaming might drive the glues further into a porous surface than usual. 
>Well, it's an idea ... my finger was certainly deeply glued to my thumb! We 
>could really use some experimentation on bond strength with different 
>setting up methods.

Sounds as if we have a similar set of fingers. <g> Chemistry is not my
strong suit, it's nice to have the 2 applications for different conditions.
>
>>I no longer tap pins on grands, why bother? time you get the block jacks in
>>place etc, the CA is well on the way to cure enough to tune.
>
>I like the idea that pins don't need tapping any more. Tapping may tighten 
>momentarily, but the contact gained is just a fraction of an inch, where 
>the bottom of the pin contacts old but uncrushed wood, and the coil gets 
>closer and closer to the plate. It looks bad, too, to have the pins 
>staggered in height, though it certainly shows which are loose.

A little trick in applying the thin CA, save an empty bottle and buy some
spare tips. Use only about an 1/8th full and it will not run all over the
plate, and it will go where it is intended. Now that's the voice of
experience, all bad. But I only did it once, honest.

Not to mention the string drag that it induces.

Roger

Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505