Tightbond Creep

[Delwin D. Fandrich]

----- Original Message -----
From: "Ron Nossaman" <RNossaman@cox.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: Sunday, April 27, 2003 11:11 AM
Subject: Re: Tightbond Creep


> ....If you ever do find documented creep
> rates for a Titebond glue joint observed under real world livable
> conditions, I'd sure like to know about it. Anyone have creep and
> compression set rate figures on spruce under the stress conditions it's
> placed under in a piano soundboard - compression crowned or rib crowned?

I've not yet done it (and probably won't) but I've wondered if you could use
plain old white glue to affix crowned ribs to a soundboard panel. I fail to
see where creep would be an issue. There is very little, if any, shear
stress on these joints. Now, in a compression-crowned soundboard assembly
you have a whole other issue....



> Laminated ribs? It wouldn't surprise me a bit to discover that the creep
> rate of spruce is considerably higher than that of Titebond, which leaves
> us where if that's the case? I've been using Titebond for bridge and
> soundboard work for over 25 years, and don't know of a glue joint failure.
> Maybe they just don't tell me when the ribs fall off.

Some years ago I set up a test of several cut curved ribs and several
laminated ribs. The radii and the cross-sections were identical. The
adhesive used for the laminated ribs was Titebond. After one year under
identical conditions and stress the laminated ribs had actually retain more
of their original crown than had the solid ribs. I've not worried about
Titebond creep since.

Del