C-A glue for pin blocks

[Newton Hunt]

Hi Paul,

> I'm not fond of shims and I don't like pins above a size 4 or of a different size than the rest in a section, if avoidable.

I have used shims with great success over the years.  I prefer to use
sandpaper, 150 grit or so, with the sand outward against the pin hole
going only about 1/2 way around the hole.  Drive the same pin back in
(or turn it in if needful no jack is available), tear or trim off the
excess paper, replace the coil and tune.  I have Laos used veneer,
about 1/8" wide, walnut or mahogany because they compress, and do the
same.  DO not use beach, maple, rosewood or other real hard woods.

> I've been on the list only 6 weeks now

Is that All?  Seems longer to me.

> 1.  Loosen 1/4 turn or so, slip off the coil and turn the pin up a little higher than it should be when at tension.

The entire point of this procedure is that you do not need to do
this.  Waste of your time.

> using a well sealed hypo syringe 

NO!!!

First use fresh, new, and trusted source CA.  Do NOT use older CA.  It
begins to thicken as soon as it is unsealed.  All CAs come with a
pointed spout and if you get the industrial quality stuff from a
trusted source like Ed Dryburg you can get tubes that can allow you to
control the length of the spout and it's inside diameter by stretching
it.

Transferring CA from one container to another will begin the setting
process immediately if there is ANY contamination in the second
container.  If this happens the syringe will freeze up and you loose
everything, syringe and glue.  ALso doing this could be dangerous and
hazardous to the glue.  If you put _anything_ in the glue you risk
contamination.  If you spill it you have major problems with cleanup.

The moisture still contained in the wood, even if very little, will
initiate the setting process, even if slowly.  The plate glass test is
not a test of CA setting process since there is no moisture in the
glass.  I like the idea of using a syringe to finely control
accelerator.

Setting and curing are two different things.  When glue, any type,
sets it is now longer a viable glue unless it is in a joint already. 
When a glue cures it has reached it's full hardness.  Think about
using "5 minute" epoxy.  You have 5 minutes before it is useless as a
glue but the curing time is 24 hours.  With CA the curing time is 4
hours from the time it sets.

> Whack pin just enough to break glue contact.

One tap, enough to cross thread the pin and I would likely not use a
jack because it is a light tap and because the stress is evenly
distributed across the glue joint, however much that is, and will not
stress the rest of the block.  If I am doing an entire piano I would
use the jack.

> When the pin gets whacked, does it really separate cleanly from the surrounding wood (and the glue itself).  Why doesn't some of the glue remain on the pin, possibly along with bits of wood from the block?

Not an issue.  If it holds, it holds, and where, how or how much is
irrelevant to it's function.  The glue soaks deeply into the wood and
adheres to the pin but if it works it works.  Try one on an old piece
of junk then remove the pin and look.  I haven't had the opportunity
yet.

> Why doesn't the pin bind and jump during tuning from rubbing against a plastic and possibly uneven surface?

It may very well do so, or at least grate a bit.  We are trying to
extend the life of something almost useless and I can put up with a
few jumpy pins.


Brenda Mamer wrote:
> 
> Hi List,
> 
> If CA glue is used, then when needed  could the  piano  be repinned using the
> original pinblock, or must the block be replaced? what about reaming and
> repinning?

When it comes to doing _that_ much work replace the block and be
assured of a good, durable job.

Have a good week all.

		Newton