More general glue questions was Glue for cracked rib?

Alan R. Barnard tune4u at earthlink.net
Mon Oct 30 11:35:29 MST 2006


Are there reasons for not using yellow glue, here? (Titebond, Carpenters, etc.)

And while I'm asking questions out of ignorance: When you need to fill a gap, what about using panel adhesive--the stuff that looks like peanut butter?

Alan Barnard
Salem, MO
Joshua 24:15



----- Original message ----------------------------------------
From: ed440 at mindspring.com
To: "Pianotech List" <pianotech at ptg.org>
Received: 10/30/2006 12:19:53 PM
Subject: Re: Glue for cracked rib?


>Gordon-

>When you say "cracked" I'm assuming you mean "separated," not "split."

>Cold hide glue is usually the restorer's choice in a situation like this. It will soften and 
>combine with any hide glue that is in the joint.  Hide glue is not gap-filling.  (I just 
>came from a great talk by Eugene Thorndahl, who has spent 50 years as a hide glue 
>chemist. He said the gap-filling properties of hide glue are an Internet myth.  
><www.bjorn.net>  He may be the only source of genuine graded hide glues for 
>instrument and restoration work.)

>For a fast repair, consider CE (Cyano-epoxy aka Tech-Bond).  It has the shear and 
>shock resistance that CA sadly lacks, and sets a bit slower.  Jim Coleman, Jr. and a 
>few other specialty distributors sell it.

>In either case you may want to drill a hole for access to the joint and inject the glue 
>right into the center of the problem.

>Ed Sutton

>-----Original Message-----
>>From: gordon stelter <lclgcnp at yahoo.com>
>>Sent: Oct 30, 2006 12:15 PM
>>To: Pianotech List <pianotech at ptg.org>
>>Subject: Re: Glue for cracked rib? ( Terry ????? )
>>
>>Thanks, Terry.
>>      I'm going to run some experiments with the other
>>glues, to "see what sticks". But I like your logic
>>about hide-to-hide ( although I think any water-based
>>glue will bind nicely with the hide glue, IMHO. One
>>thing that "came to me in a  dream" is this: I have
>>the piano rolled up on its tail so the ribs are
>>horizontla, and WAS intending to drip super-thin CA
>>into the rib crack from the side ( the only type thin
>>enopugh to make it in there, probably ) with the
>>portion of the crack on the other side of the rib
>>"dammed up" with masking tape, to keep the CA from
>>just dripping though ( and all over the place ). But
>>then I rememberered that the glue on tape "activates"
>>the CA, so I might not have time to "pul it all
>>together" with the clamps. So I'll run some tests with
>>this. 
>>      3 ribs are cracked ( so much for over-drying
>>boards! ) but only one crack is wide enough to get an
>>exacto-knife into. So I'm goping with the ultra-thin
>>CA< and leave it all clamped tightly together for
>>several dauys.
>>     I'll let y'all know how it turns out.
>>      Peace,
>>     G
>>
>>--- Farrell <mfarrel2 at tampabay.rr.com> wrote:
>>
>>> The few times I've done this repair I have used cold
>>> hide glue. I figure 
>>> there is still hide glue on the glue surfaces, so
>>> more hide glue would 
>>> likely stick the best. It has good gap filling
>>> properties and is easy to 
>>> use. I really don't see what would be better.
>>> Adhesives such as epoxy and 
>>> others are only as good as your surface preparation
>>> - and there will be next 
>>> to none with this repair.
>>> 
>>> Terry Farrell
>>> 
>>> ----- Original Message ----- 
>>> > Thanks, Terry.
>>> >     I just made some of these. But the question
>>> > remains: what glue? Bolduc? Epoxy? CA? I'm tempted
>>> to
>>> > try ultra-thin CA, simply because it is the least
>>> > viscous, and should wick into the rib crack well.
>>> > First I plan to blast out the crack in the rib
>>> with
>>> > brake part cleaner and one of those pipette tubes
>>> that
>>> > comes with it,  as these is some residue in the
>>> rib
>>> > crack from stripping the board ( with straight
>>> acetone
>>> > ) that went through the soundboard cracks to
>>> below.
>>> > Then I'lll roll the piano on its tail so that the
>>> ribs
>>> > are horizontal, and glue dripped on the crack from
>>> the
>>> > side will fill it well. Then I'll put in the wire
>>> type
>>> > clamp, and waita  few days. Question: I don't have
>>> any
>>> > CA accelerator, and none is sold in thios town.
>>> What
>>> > else might help it cure ?
>>> >      If the wire doesn't want to come out, I'll
>>> try
>>> > heating it slightly. Heat softens cured CA>
>>> >     An alternative ( that I've used to get glue
>>> into
>>> > tight spaces ) would to be to squeeze an exacto
>>> knife
>>> > blade into the rib crack, after drilling a tiny
>>> pilot
>>> > hole from above, poutting the drill bit back in to
>>> > make sure that the blade stops it, then drillinga
>>> > slighly larger hole ( like 1/8" ) from the board
>>> side,
>>> > and fliinig it with glue. With the blade still in
>>> > place, or with the intitial, smaller bit stuck in
>>> the
>>> > back half of the hole, glue can then be squeezed (
>>> > witha  hypo ) into the 1/8" hole, and the 1/8" bit
>>> > turned around and used as a piston to force it
>>> into
>>> > the joiunt. This works very well to get glue into
>>> > tight spaces.
>>> >     What would you do?
>>> >     Thump
>>> >
>>> > --- Farrell <mfarrel2 at tampabay.rr.com> wrote:
>>> >
>>> >> I have found using little boat clamps to be very
>>> >> useful for jobs like you describe:
>>> >>
>>> >>
>>> >>
>>> >> Plenty strong to pull anything together.
>>> >>
>>> >>
>>> >>
>>> >> Terry Farrell
>>> >>
>>> >>
>>> >> ----- Original Message ----- 
>>> >>
>>> >> > I'm going to use a "piano wire tgrough the rib"
>>> >> type
>>> >> > clamp. Of course, I'll "dry run" it, first, too
>>> >> see if
>>> >> > it's strong enough to oull it back together.
>>> >> >     G
>>> >>
>>> >
>>> >
>>> >
>>> >
>>> >
>>>
>>__________________________________________________________________
>__________________
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>>> > 
>>> 
>>> 
>>> 
>>
>>
>>
>> 
>>__________________________________________________________________
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