Acoustic Guitar Construction

I have a set of figured koa sides that I got too happy on the drum sander with. Have any of you laminated sides? I am considering Backing these up with mahogany and thickness sanding again. If I do this how will they behave when bending? Will they come apart? I use an old fashioned bending iron.

I believe Dave Bagwell has done some laminating of sides with success.
Perhaps he'll chime in.

I've laminated sides but only after bending them separately. Don't know how it would work bending after gluing or what glue to use. Maybe painting both pieces with HHG and not worry about getting them stuck together before bending. The heat from bending should reactivate it, or not?
I used Smith's All Wood Epoxy in a form made by bolting the two halves of an outside mold together (with spacers to get the width needed) also the spreaders. Then lots of F clamps to squeeze it all together. There's also a piece of Formica counter top in the sandwich to smooth out the clamping and waxed paper to prevent sticking it to the mold. PIA but it worked. I'll look for photos....

Found 'em....

Hee Kenny,

I used Titbond III for gluing purfling together. And it did hold well under bending. You could try that, but distroying nice koa is sad.
Herman

I have laminated 2x.045" = .090" sides many times. The basic idea was taught to me by Brian Burns. He made a movie of the process. Here is an entry I made to a forum:


deadedith

Re: Laminated sides

Post by deadedith » Sat Aug 11, 2012 2:16 pm
I gave a number of reasons I've found for saying "Yes!" to laminating. There are a million opinions on every single thing in lutherie! Here are a few from the web, just google the subject and read until your eyeballs fall out - and in the end, you just have to make up your own mind. But clearly, top-tier luthiers do use laminate, and have compelling reasons.
As always, Rick's contribution is well thought out and to the point. I happen to disagree with some of what he say, but then, he's Rick and I've only built 10.


Bogdanovich:
In a set of guitar sides one of the most important characteristics is stiffness. Laminating the sides of your guitar will produce stiffer sides than a solid piece of wood steam bent as described above. Also, steam bending is difficult to repeat accurately. Therefore, if the shape of the guitars sides differs from the ideal (drawing) the amount of volume (cubic inches) inside the box will change as well. Changes in the size of this space from guitar to guitar will have an effect on the resonance of the cavity which may produce inconsistent results acoustically.

By laminating you are in effect removing a heavier wood and replacing it with a lighter wood which will reduce the weight of the instrument. On a classical guitar this is an added benefit. The laminated sides will also be more stable over time and less prone to
cracking.

Oberg guitars:
This guitar has sides laminated from 5 layers of Brazilian rosewood. This method results in sides that will never crack and are very rigid. The back is laminated from 3 layers of Brazilian rosewood.

Deerhead guitar:
M any of Breslin's classical and flamenco guitars utilize laminated sides, designed for extra strength and stiffness, maximizing the amount of energy transmitted between the soundboard and back. Lamination also helps prevent side cracks, especially when Brazilian rosewood is worked at such low tolerence levels.

Klepper:
I build with very rigid sides. In most cases I use a double side--two layers of wood laminated together. The inner layer is usually mahogany, but in some cases will be walnut or East Indian rosewood. These double sides should not be confused with the plywood sides used on some factory guitars. The double side method is used, for example, on the guitars of the renowned classical maker Daniel Freiderich, and on the most expensive classical concert model made by Jose Ramirez. Once the sides are laminated, they will hold their shape without being clamped into a mold. They are far more resistant to cracking than a standard side

Hey Dave! Good to hear from you. How are you feeling? That radiation stuff is not for sissies is it? I still have issues a year and a half later.
So you're deadedith ehh! Lots of ANZLF threads from that name.
Is there a link to Brian Burns' process? I would like to try it again. The first two times were a bit of a struggle and I'm sure there is a better way. Can the sides be glued prior to bending? I use a Fox type bender with a blanket.

Carl