rib glueing

[Delwin D Fandrich]

----- Original Message -----
From: "Garold Beyer" <garbey@wingsisp.com>
To: <pianotech@ptg.org>
Sent: January 06, 2001 1:32 PM
Subject: rib glueing


>  One question I have concerns clamping pressure. The Davies press gives
> 100 PSI which seems excessive compared to the Hughes variant at 35 PSI
which
> seems more reasonable to me.

Some tests I conducted a few years back indicated the best pressure range to
use when gluing spruce ranged between approximately 35 and 60 psi. Much more
than this and glue joint starvation began to affect the structural quality
of the bond. (Depending on the viscosity of the adhesive, of course.)



>  Another question concerns bottom caul configuration. If one is using
> straight ribs and compression crowning (I am), does pressing into a curved
> surface have any material effect on the crown or is Jack Krefting correct
> when he stated in one of his series of articles that it does not.

Huh?  Of course it will have an effect on the resulting crown.



>  Also, I plan on using the individually inflatable system with "Schrader
> valves" as in the Hughes article but must confess these are unfamiliar to
me
> and I need to know where to obtain them

Schrader is simply a manufacturer of air and hydraulic valves. Visit you
local industrial supplier or air system distributor.



and also what sort of supplier I can
> try to locally get 1 1/4" mill hose.

Visit your local fire department and see if you can scrounge some of their
used fire hose. Also, check with them for the name of their supplier. Else,
it's back to your favorite industrial supplier.

Del