Bridge Construction Method

[Farrell]

And if you epoxied that veneer onto the outside of the dogleg curve, wouldn't that help to keep the sound in? Oh, wait a minute - epoxy is a good vapor barrier, perhaps it doesn't preclude the passage of sound. Ok. Never mind. Maybe if you aim it in a optimal preferential direction?

Terry Farrell
  
----- Original Message ----- 
From: "Ron Nossaman" <RNossaman@cox.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: Saturday, April 19, 2003 12:19 PM
Subject: Re: Bridge Construction Method


> 
> >Let say we want to make a vertically laminated long bridge with nine 3.6 
> >mm thick laminations. That will give you a bridge about 33 mm wide. The 
> >figure below represents unbent laminations in the area of the troublesome 
> >(for me anyway!)dogleg. What about laying up the laminations as below, 
> >having let's say five (whatever in reality) laminations be continuous 
> >through the dogleg, and the others terminate on either side of the dogleg. 
> >Bend gently (never any more bend needed than in the sections not at the 
> >dogleg), glue, and then trim the normal-looking dogleg curves with bandsaw 
> >and sand. You've got a large overlap at the dogleg, I can't imagine there 
> >would be any loss in strength - not torturing the maple laminations, 
> >perhaps there would even be an increase in strength. As long as we are not 
> >interrupting the "circle of sound" (heaven forbid!), I should think this 
> >would ease the task of dogleg-making, allow the use of thicker laminates, 
> >and give you complete freedom to make the dogleg dimensions (curve radii) 
> >any size you want - you will be simply cutting these cosmetic curves 
> >rather than having the curves originate from the integral bend. Heck, be a 
> >radical - leave them squared-off as plate configuration allows!!!!!!!!!
> >Waddaya think?
> >
> >Terry Farrell
> 
> 
> But won't the sound leak out the open end grain at the doglegs and pile up 
> in the killer octave area? I suppose it could be swept out occasionally if 
> it proved to be a problem. It's a good thought, and I don't see any reason 
> to think this won't work just fine. The joint will be stronger for longer 
> than the often used scarf in solid bridges, not to mention the continuous 
> through strips and should be easier to build than full continuous vertical 
> laminations. I don't see a problem, and a veneer strip glued on both sides 
> after the doglegs are contoured and before capping will turn it into a full 
> continuous vertical lamination bridge until someone replaces the cap some 
> day and finds out different.
> 
> Ron N
> 
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