How does CA cure?

[Susan Kline]

Hi, Roger


>                As far as I'm concerned it's the magic elixir for field
>repairs, the red Hot Stuff is usually tunable after 30 min. I use NO
>accelerator and dose several applications at about 5min intervals.

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?

>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. 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.

>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.

Susan