More general glue questions was Glue for cracked rib?

[ed440 at mindspring.com]

Alan-

Depends on just what you mean by "here."

For a buzzing rib in a dying piano with no rebuild value in a school struggling to recover from Katrina, I would use whatever would work fast and easy. (Probably CE, and I might press the rib up with a wedge or stick to the floor or just my hand for the minute it takes the glue to bond.

For repair, rebuilding or restoration of a preWWII instrument, working in my shop, I would probably use cold hide glue.  (First I would test glue some scrap wood over night to make sure my glue was still good.)  A failed hide glue joint usually has glue dust or flakes. You can't fully clean it without disassembling the joint.  Cold hide glue is fairly thin, easy to inject and will dissolve the glue dust.  It gives you plenty clamping time and can be reversed later with water and heat.   

To use Titebond you need to get the joint cleaned, it is a bit thicker than cold hide glue and harder to reverse, should that be desired, and you've got to clamp faster.

On a Kimball Classic with a soundboard coming loose along the spine, I used Titebond and quickly clamped with a strip of quarter round and drywall screws.  This job was done on site.

On a rare 19th century piano I'd consider refering the job to a conservator trained to deal with historic instruments or at least getting specialist's advice on what to do (or not do).

I would not use the peanut butter stuff.  For gaps I like polyfiber in epoxy. For cosmetic reconstruction try Wood Rebuilder.

Just my opinions.

Ed Sutton



-----Original Message-----
>From: "Alan R. Barnard" <tune4u at earthlink.net>
>Sent: Oct 30, 2006 3:42 PM
>To: pianotech at ptg.org
>Subject: More general glue questions was Glue for cracked rib?
>
>----- This is a forwarded message ----------------------------------------
>From: "Alan R. Barnard" <tune4u at earthlink.net>
>To: ed440 at mindspring.com, pianotech at ptg.org
>Received: 10/30/2006 12:35:29 PM
>Subject: More general glue questions was Glue for cracked rib?
>
>
>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