hide glue "tradition"

[Susan Kline]

Dear Stephen,

This is _really_ interesting. I assume you size with the same thin glue? How
long would you let it sit then, before gluing?

Thanks for the information. I have a toothing plane iron ... Maybe I should
build a body for it!

Susan.
--------------------------------------------
At 02:23 AM 8/19/97 -0500, Stephen wrote:
>> Please elaborate - how DID the old guys do it???
>> 
>Three things:
>1. Tooth all glued surfaces
>2. Size everything
>3. Use ultra-thin glue. Make thin glue, thin it until it looks like it 
>wouldn't glue anything, then add more water. Then it's thin enough.
>
>Why?
>Toothing improves the bond and allows the extra glue somewhere to go when 
>you clamp the joint. Thin glue is very easy to expel from the joint and 
>requires less clamping pressue consequently. (After all that's why we 
>clamp.) Old toothing planes are lurking everywhere...they weren't just 
>used on veneers. In any case you only have to look to see toothed 
>surfaces everywhere.
>
>Sizing prepares the wood and makes it behave. Unsized wood will suck out 
>the water from the glue almost as soon as you put it on, thus requiring 
>pre-heating as a last-ditch effort to make things last long enough to get 
>the clamps on. Thin glue can only be used on sized surfaces. Evidence for 
>sizing is clear on almost any old artifact, piano, organ, furniture etc.
>Sizing was often done en masse. The old organ builders sized more wood 
>than a railway trestle bridge needs.
>
>Evidence for thin glue is clear on old pianos...you can see the long thin 
>runs that have been expelled from the joints. Glue that is the thickness 
>we are "supposed to" use nowadays does not flow in this manner. The runs 
>are so precise and long that you can even use them to analyse how a piano 
>case like a Graf was assembled.
>
>By the way there is such a thing as "bad" glue...and there seems to be a 
>lot of it floating about on this continent. Take care. Also never heat 
>hide glue over 60C or it is impaired (see Wolfenden on hide glue)...in 
>fact any temp. below 60C that the glue is liquid is acceptable. The old 
>guys didn't use thermometers.
>
>You can't tell by looking at broken down pianos whether the surfaces were
>pre-heated. But there is clear visible evidence for the above three
>points. And experience shows that the method works with no heating. 
>Heating every piee to glue is a royal pain in the butt, so you can bet the
>old guys would not have pre-heated. They weren't stupid. 
>
>[No claim to having discovered the method above...credit is due to my 
>colleague Bill Jurgensen, an ex-patriot US organ, harpischord, piano, 
>violin maker who lives in Germany. Evidence on organ cases and pipes is 
>even more obvious than in pianos. There isn't much harder to glue than a 
>windchest on a cathedral organ...no pre-heat needed.]
>
>Stephen
>
>Stephen Birkett Fortepianos
>Authentic Reproductions of 18th and 19th Century Pianos
>464 Winchester Drive
>Waterloo, Ontario
>Canada N2T 1K5
>tel: 519-885-2228
>email: birketts@wright.aps.uoguelph.ca
>
>
-----------------------------------------------
Susan Kline 
P.O. Box 1651
Philomath, OR 97370
skline@proaxis.com

"I march to a different drummer, whose location, identity, and musical
training haven't yet been established."
			-- Ashleigh Brilliant