laminated bridge question

[Ron Nossaman]

>This refers to the method I mentioned for laminating by cutting the
>laminates and keeping them all attached to a solid piece. I don't really
>think that is practical or necessary for a modern bridge. There are too
>many layers, for one thing. There is no real benefit, since there is no
>straight un-laminated part on a modern bridge. 

*Then why in the world did you suggest this method as justification for my
using hide glue instead of Titebond when you knew full well it wasn't
appropriate? 



>Here's what I would do for a modern all-laminate bridge: 
>--
>Resaw and surface a couple of laminate thickness veneers say from 6 in
>stock. Go over these both sides with a fine (scratching = high angle)
>toothing plane and size both sides (no more than 5 minutes work). After
>the size is dry cut them into the appropriate number (e.g. ten) of strips
>on the bandsaw. Lay the strips on the gluing table side by side. Coat en
>masse with thin glue using a wide brush (few seconds). Because you sized
>and are using thin glue, your working time is surprisingly long (without
>the need for urea)...unsized wood draws the water out of the glue causing
>it to gel much more rapidly. Put all the strips together, line them up in
>the cauls and clamp. The thin glue and the toothing means you only need
>light clamping to expel the glue completely from the joint surface.  The
>toothing and sizing itself add almost no working time at all to the job. 

*Other than the light clamping pressure, which will prove to be a mistake
very quickly, it would appear to be possible. Possible, however, does not
mean preferable. You still offer no reason that I should prefer hide glue to
Titebond to laminate bridges, other than the possibility that I may spend
more time per job with hide glue. I will apparently still have saved five
minutes by using Titebond and not toothing.


>> How many laminations are there in one of your Viennese frames? What's
>> the minimum radius bend? How many people does it take to muscle the beast
>> into shape? 
>>
>Graf and Streicher frames are constructed with horizontal layers put
>together like brickwork. A Streicher has 6 x 1 inch layers of spruce with
>a 7th maple liner layer on top of that. You work on the layers one at a
>time, using gobars and clamps. There is a large surface area and some
>tricky clamping required...a single layer might need up to 40 gobars and
>60 screw clamps. Once you get it assembled it looks like a jungle.  Even
>so, the frame goes together fast. Working alone, one day per layer is
>sufficient to cut, fit, tooth, size, assemble and clamp. So one person can
>make a frame in about a week, with time for beer. The outer spruce case is
>glued later to the inner frame like a skin. The 5 mm bentside is forced
>into position as you clamp it in place... it can be done
>safely with just a single person. To the outer case 2 mm veneers are
>bookmatch glued vertically, outside amd inside above the soundboard. 

*So it's not done in one pass, like a laminated bridge. That's what I
figured. Since it isn't remotely the same type of assembly, again, why was
it held up as a justification that I should abandon Titebond and use only
hide glue to laminate bridges? We seem to be back to my original post, which
has been addressed to my satisfaction, unless you have anything else.

>Stephen

 Ron