Laminating and Bending, was: warped keys

[Farrell]

I have a Baldwin M (5' 2" or so) in my shop that I will be making a soundboard for soon. I thought it would be a good idea to make a display soundboard for lectures and marketing purposes. So I glued up a 10 laminate rim the exact dimensions of the Baldwin M inner rim. When I make a board for that piano, I will also make a duplicate soundboard and mount in on the pseudo-rim.

It was interesting making the rim. The laminates are just a bit over 1/8" thick and only 2" tall. Any thicker and the laminate would break when bending around the tight curve of the treble. I first glued three layers together. After drying, I removed the clamps. The rim spread apart a good foot or so where the belly rail would be (rim has the three sides and is open where the belly rail will go). Then I glued two more layers on. After drying and removing clamps, it only sprang out about an inch. Two more layers for a total of 7 laminates and there was virtually no movement when removing clamps. I then added the last three layers. Unclamped and there is absolutely no movement. 

I had done laminating before, but never with so many layers, and not such complex and tight curves. Put enough layers on there and the darn thing is frozen in place forever. Amazing.

Terry Farrell
  
----- Original Message ----- 
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Friday, January 10, 2003 11:46 AM
Subject: Re: warped keys



----- Original Message ----- 
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: January 10, 2003 4:51 AM
Subject: Re: warped keys


> Time, heat and pressure can even put a nice bend in a mountain. Regarding the rims though, the thickness of the lamination is also important. The thicker a piece of wood is (like a key), the longer heat and pressure will be required to bend it.
>

Some very early (forte) piano rims were heat bent out of solid stock. A few have been made from stacked, sawn stock. From the mid- to late-1800s most all piano rims have been made from bent, laminated veneers of varying species and thicknesses.

Heat bending solid stock (with or without steam) into a piano rim is problematic at best. The inconsistencies of the process pretty much insure hand fitting everything on through the process. Bent laminates are quite consistent -- assuming you maintain control over the process.


> 
> You could do the key in a steam box. That is how you go about bending 2" by 2" (and larger) white oak to make a bent rib for a boat hull. Some woods steam better than others. If you steamed the whole key though, I guess you'd have to plan on rebushing and a new key cover. But yes, it would most certainly work. Don't recommend it though.
> 

Not to mention the fact that all piano keysets are made of glued up blanks. The glue joints holding the individual boards together are going to want to come apart as well. What you're going to end up with are lots of bits and pieces to glue back together. Ain't we got fun!

Del