Plugging capstan holes

[David Love]

Terry's post has a good outline of the products from West System.  As Ed
mentioned, the microlite fairing filler (#410 from West System) when mixed
with the epoxy creates a low density compound that behaves much like wood
and is easy to drill, sand, and tap capstans into.  I find that the epoxy
creates a more uniform drilling body than dowels with no gaps or end graing
that tend to cause the drill to wander off in an unintended angle or
direction.  Also, capstans do not turn as smoothly when tapped into the
endgrain of a dowel, though I'm not sure why.  Also, it's very fast. 
Fifteen to twenty minutes to fill the holes the first time, do something in
the shop and in a few hours spend another twenty to thirty minutes to
smooth them over.  After it hardens, ten minutes with the orbital sander to
clean it up and the new capstan line is ready to mark and drill.  Cutting
plugs, drilling, trimming and sanding takes several hours and I'm not sure
the result is better.

The glue injector is very useful for this operation.  I get them from
Pianotek (www.pianoteksupply.com) #GI-2 about $10.00 for a dozen.   It's
important to be able to inject the glue all the way down to the bottom of
the hole and as you squeeze the injector you can back the tip out filling
the hole as you leave it.  That way you don't have to have an pinhole at
the bottom to release air (which tends to make a mess underneath the keys)
or attempt to pour this thickened concoction out of a mixing cup into a
small hole.  The syringe has a hole wide enough to allow the epoxyto flow
through it  even with a lot of the fairing compound added.  They are cheap
and disposable.  Mix the epoxy in a mixing cup and then pour it into the
injector, insert the plunger and your off.

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Isaac OLEG <oleg-i@noos.fr>
> To: <davidlovepianos@earthlink.net>; Pianotech <pianotech@ptg.org>
> Date: 5/19/2004 7:27:26 PM
> Subject: RE: Plugging capstan holes
>
> Hi Dave, what is Microlite ?
>
> Thanks for your detailed explanations, it is interesting.
>
> Are some epoxy quality more easy to drill and tap than others, or is
> it mostly the added powder that helps the final material to be easy to
> work with ?
>
> I have bought along the grain dowels from a wood merchant. these are
> used to plug knot holes in wooden floors. They are not very round, but
> suitable from 8 to 12 mm , in hard woods.
>
> But the epoxy method seem fine indeed.
>
> best regards.
>
> Isaac OLEG
>
>
> -----Message d'origine-----
> De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la
> part de David Love
> Envoye : mercredi 19 mai 2004 23:26
> A : Pianotech
> Objet : RE: Plugging capstan holes
>
>
> I fill the entire hole with epoxy.  West system and a generaous amount
> of
> microlite (410).  Put it in a glue syringe and fill them up.  I insert
> the
> syringe all the way to the bottom and back it out as squeeze to get
> the
> stuff to the bottom of the hole.  The top usually sags a bit and so
> you
> need to go over it a couple of times within, usually, about 30
> minutes.
> Even then the stuff will eventuall sag a bit leaving a slight
> indentation.
> I've dealt with this two ways and I'm not really sure which I prefer,
> but
> both work.  First, let them sag to slightly below key level.  After
> the
> epoxy starts to set up--the slow set stuff will harden quite slowly
> but
> reaches a point where it will not sag anymore--I mix up another batch
> using
> both microlite and colloidal silica (406).  Mix it to the consistency
> of
> whipped butter or mashed potatoes and then take an artists palette
> knife
> and fill in the small indentation flush to the key top.  When it all
> hardens sand smooth with an orbital sander right in the key frame.
> You can
> block the key ends to hold them more steady.  The other method
> involves
> adding a bit more of the original batch out of the syringe as it
> starts to
> thicken so that it sets up higher than the top of the key stick.
> Before it
> totally hardens trim with a sharp chisel (wax it a bit first to keep
> it
> from sticking) or a sharp japanese knife.  Clean up with an orbital
> sander.
>
>
> I don't like using dowels to plug the holes because I don't like
> drilling
> and screwing capstans into the endgrain of a dowel.  You can, as some
> do,
> cut plugs out of old keys, drill the hole larger to cover the
> coutersink,
> plug and trim.  I find that it takes too long.  The epoxy holds the
> capstan
> just fine and, once hardened, drills and taps without any problems.
>
> BTW  make sure that the old capstan holes aren't drilled all the way
> through the key.  Yep, I did find that out the hard way.  Thought I'd
> entered the Twilight Zone with a capstan hole that just never seemed
> to
> want to fill up....imagine if you will..
>
> David Love
> davidlovepianos@earthlink.net
>
>
> > [Original Message]
> > From: Phillip Ford <fordpiano@earthlink.net>
> > To: <pianotech@ptg.org>
> > Date: 5/19/2004 11:39:28 AM
> > Subject: Plugging capstan holes
> >
> > Would anyone care to offer some advice on plugging capstan holes?
> They
> are often countersunk, so if you glue in a dowel that's level with the
> top
> of the key there will be a gap or open ring around the dowel.  If you
> happen to be drilling near this area it makes the bit wander.  If you
> epoxy
> in a dowel and fill in the gap with epoxy it's pretty hard to level
> them
> until the epoxy hardens.  So you essentially have to leave the dowel
> sticking out a bit and the epoxy mounded up a bit.  This means a lot
> of
> sanding or filing after the epoxy hardens.  My current modus operandi
> is to
> glue in a dowel that's a bit shorter than the hole and punch it in so
> that
> it's a little below the top of the key.  I then fill in the divot with
> epoxy and level with a razor blade before the epoxy sets.  Other
> ideas?
> Does anyone fill in the entire hole with epoxy?
> >
> > Phi Ford
> >
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