How does CA cure?

[Diane Hofstetter]

Susan,
Last night I put several size 1x0 pins in a size 2x0 hole, poured ca glue in 
until it stopped disappearing into the hole.  Went out to the shop several 
hours later, broke the pins loose and removed them with a drill.  Out popped 
pins coated with a ca glue sheath.  The sheath could be easily broken off 
the tuning pins, but it had it's own integrity, I don't think it would have 
crystallized or any such thing inside the hole.

I first used CA glue in a pinblock about 7 or 8 years ago to try to deal 
with excessively loose pins in an institutional environment where they will 
never spend the requisite money to rebuild the piano. The pins still hold 
well after two tunings a year for all those years.

Diane


>From: Susan Kline <skline@proaxis.com>
>Reply-To: pianotech@ptg.org
>To: pianotech@ptg.org
>Subject: Re: How does CA cure?
>Date: Tue, 16 Nov 1999 19:27:08 -0800
>
>At 08:30 PM 11/16/1999 -0600, you wrote:
>
>
>> > I believe that using the kicker when doping pinblocks may be a mistake,
>> > because it might set up the top layer, leaving the rest, deep in the 
>>hole,
>> > sealed in so that moisture and air can't break down the stabilizer.
>> > However, this is merely conjecture on my part.
>> >
>> > Susan Kline
>>
>>As long as we are on conjecture, I can imagine the action of CA glue on
>>tuning pins.
>>
>>It "glues" the pin to the sides of the pinblock hole.  When the pin is
>>turned this
>>breaks the bond. The pin now is coated with bits of dried glue and broken 
>>off
>>pinblock crumbs. The pin is now held because it is rough as in a
>>rasp.  And the more
>>it is turned as in tuning..... are you getting the same picture I
>>am?   The reason
>>for my conjecture is that once I put CA on bass T pins, and voila they
>>were tighter.
>>
>>Then I had to let the bass strings down and when I turned them back up, 
>>not so
>>voila, as in,  as they were.   ---riconjecture
>
>Dear Ricon,
>
>As an alternative picture, perhaps when the joint breaks the glue stays
>stuck to the wood, which is porous, and takes with it a thin layer of metal
>corrosion from the pin?
>
>Maybe whoever has a totaled old wreck might drip in the CA, wait a week or
>two, turn a few pins to break the joints, and then chop the whole thing
>open to see what is there?
>
>Susan

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