BobDavis88 wrote: > Del writes, > > > >My personal preference is a vertically laminated body and a horizontally > > laminated cap. > > Del, > > Having had experience with the design of such bridges, can you give us any > general guidelines about how they relate to the standard vertical w/cap? > > 1. What laminar thickness and grain orientation are you speaking of for the > base? For the cap? > 2. What kind of glue? > 3. What approximate differences in cross-section and height could one expect > to produce a bridge of the same stiffness/impedance/transmission/whatever? > 4. Have you used this in rebuilding, i.e., a standard vertical base planed > down to accept a veneer laminate cap? Or does this change the impedance enough that this really needs to be done from > scratch? > > Not having heard a great-sounding piano with a laminate cap, we have always > used a quartered maple cap, but only because we didn't know enough. Vertical laminate base/horizontal laminate cap > certainly has some attractive physical properties. > > Thanks for the informative posts. > > Bob Davis -------------------------------------------------- 1) I'm not sure it matters all that much what you use for the body of the bridge. My personal preference is a vertically laminated body simply because it is fairly easy to make consistently. For caps I prefer horizontally laminated material using maple veneers approximately 1.5 mm thick. I've used Delignit laminated beech bridge cap stock and liked it a lot except that they use resorcinol resin adhesives which are very dark red/brown in color. I thought it looked good but we did have some complaints from customers. 2) Any adhesive can be used that is reasonably rigid when it dries/cures can be used. I prefer either a urea- formaldehyde or a phenol- formaldehyde adhesive for both the body and the cap. (Before anyone asks -- no, I've not tried CA glue!) 3) Yes, cross-sectional dimensions will affect the stiffness of the bridge. These are generally chosen by the designer to give whatever effect he/she may be after. Changing from a solid bridge to a laminated bridge of the same dimensions will change both the stiffness and the mass to some degree. It's a little hard to predict, though. The mass can be checked by weighing the two -- before and after. Not having done this I can only guess that the laminated bridge might be heavier. This could easily be corrected by shaping or drilling it a bit if the differences were significant. I would also guess that the laminated bridge might be a bit stiffer. In my view, this would be an advantage and I would not worry about it. 4) Yes I have. In fact, once we have our press operating again and we locate a good source for hard maple veneers, I'm going to switch all of our bridge capping back to laminated stock. We make no compensation for the differences in material when we use laminated capping stock vs. solid vertical grain stock. Regards, Del PS. Now you can help me. Do you (or does anyone else out there, for that matter) know of a reliable source for good quality hard maple veneers? Our old supplier in Ohio is no longer in business. Thanks in advance! -- ddf
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