Glue for laminated rib construction

[Delwin D Fandrich]

As did I some 30 years back when I first started laminating ribs. Then I
switched over to a urea formaldehyde adhesive and then to Titebond II and am now
back to my old favorite, a urea formaldehyde.

I did manage to cure the instability problems with Titebond by leaving each
batch in the clamping cauls for a couple of days. It worked but it always made
me feel a bit uncomfortable. So I've gone back to my old standby, #CP-0503 -- a
powdered, pre-catalyzed urea to which you add water. I get it from CP Adhesives,
www.cpadhesives.com, (which used to be Custom Pak Adhesives). It runs $18 for
5-lbs or $70 for 25-lbs. I don't know how this price compares to the others.
(Which all reminds me -- I have to order some more for a large laminated
structure I'm getting ready to glue up.)

CP-0503 has a shelf life of a year or better (as long as you keep it closed up
tight and reasonably cool) and it mixes with water. The company says it will
cure at anything from 70º F on up but I've used it down to about 65º with no
problems. It has minimal gassing. I use it with moderate ventilation with no
problems.

Del
Delwin D Fandrich
Piano Design & Manufacturing Consultant
620 South Tower Avenue
Centralia, Washington 98531  USA
Phone  360.736-7563
<mailto:fandrich at pianobuilders.com> 

| -----Original Message-----
| From: pianotech-bounces at ptg.org 
| [mailto:pianotech-bounces at ptg.org] On Behalf Of Farrell
| Sent: October 11, 2007 11:54 AM
| To: Pianotech List
| Subject: Re: Glue for laminated rib construction
| 
| Because I've had a few slabs of ribs change shape after 
| drying out. After a week or so, once MC is equilibrated to 
| the shop I'm sure they are fine. But I've made up a few slabs 
| with a curve of X meters and ended up with X-? meters or X+? 
| meters. Not a big deal even then, cause I can still use 'em. 
| But it can be frustrating if you want to make a certain 
| radius and use that certain radius. I simply found that with 
| the Unibond UF adhesive that is never an issue.