VIDEO- Laminating Sides

Beau Hannam Ukuleles

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My method for laminating sides (guitars and ukes)

GLUES-
I use Titebond 1 (redcap) as I don't have to wear gloves as you have to when using Epoxy or the Gorilla poly foaming glue stuff. It all works. Epoxy has the benefit of having no water content (hence why i use it the glue the fingerboard to the neck) but as i don't get any problems laminating sides with T1 i don't find it necessary to use epoxy.

WOOD THICKNESSES--
There is no correct (or even best) thicknesses but I use thinner pieces for ease of hand bending.
My total side + solid lining thickness is about 8mm which is what typical single sides + factory kerfed linings are.

~ My typical layup is 0.070" outer (1st), 0.060" middle (2nd) and 0.020" (3rd) inner veneer.
~ Some luthiers do 0.080" and 0.080" or 0.050" and 0.20"
~ Other luthiers do a 0.070" outer, a 1/4" thick inner kerfed core and 0.020" veneer (for a total of about 8mm)
~ PS- Torres did just one side of 0.040"!!!- super thin.

2 or 3 PLY??
~ I do both.
~ I only do 3 ply if the 2nd layer doesn't match the 1st outer layer. So if my 1st outer layer is rosewood, and my second layer is mahogany, I would add a 3rd layer of rosewood veneer to vaguely match the outer. (you could also stain the mahogany a darker rosewood colour but that can get messy).
~ If I did a brazilian rosewood 1st outer layer and an indian rosewood 2nd layer, I would probably leave it at a 2 ply.
~- if the 1st layer is koa and the 2nd layer is rosewood, i would add a 3rd inner layer of something like maple (which would get some golden shellac), or mahogany or even some plain koa veneer- just anywood to vaguely match the general color of Koa.

~ Some do a black 3rd layer which can look nice but I like the inside back to vaguely match the inner sides if you are glancing at it.

In this video i had Paulownia (1st) + indian rosewood (2nd), so to match it up I added a maple 3rd inner.

CAULS-
There are many ways go about using cauls- Thin strips of plywood with cork, segments of the shape, or a full inner caul- I've used all- the full inner caul is best but takes a bit of work to fit correctly and you are locked in to the side thickness. I would suggest using the strips of ply until you know what side thickness you like.

You can also use a vacuum bag- but I don't.


 
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Hey Beau, have you tried a kerfed core "structured" side yet? I made up a sample one and really liked how it turned out. I used a western red cedar core, in a show face and inner veneer. I was concerned about weight, but it finished out at 15% heavier than my normal two ply sides. I don't know enough to say if it makes a better instrument, but it does make for a clean interior (no kerfing) and very stiff sides. I'm going to try it on a baritone.
 
Hey Beau, have you tried a kerfed core "structured" side yet? .

I've not yet- maybe one day when i have some spare time.

I actually prefer the look of having at least some linings in the interior. Most (all?) don't use any linings when doing the kerfed core (they aren't needed, but like i said, i prefer the look as of today- sometimes i wake up and realise i like the look of something i previously didn't like- change is good :)
 
3.8mm sounds very stout for ukulele sides. I thought most uke sides to be 2mm or less, maybe as thin as 1.5mm, and uke sized kerfed lining are 4-5mm wide (at widest point).

I'd guess your sides are very stiff as a result. Does this have a big impact on sound?
 
3.8mm sounds very stout for ukulele sides. I thought most uke sides to be 2mm or less, maybe as thin as 1.5mm, and uke sized kerfed lining are 4-5mm wide (at widest point).

I'd guess your sides are very stiff as a result. Does this have a big impact on sound?

Stiff sides with mass effects sound (for the better). I do it for a reason.
 
FWIW, I've tried vacuum bagging my laminated sides (at 22Hg) and found that there were voids in the finished sides. Mechanical clamping works much better.
 
Saltytri,

2 reasons I can think your sides had voids....... 1) material pressing was too thick for the bend...... reduce thickness and use more layers.... 2) clamping fixture didn't adequately do the job.... The most accurate way to make a fixture would be to model the side profile with both positive and negative molds. In our case we always use a cnc to cut the profiles as we have cad files of all our instrument builds....... The lbs per square inch that a vacuum bag can obtain with the bag extracted is incredible with right fixtures.

kw
 
All good points, Kevin. I figure that the fixes necessary to make bagged sides aren't worth the effort, as mechanical clamping is a very effective and easy to implement. I do bag laminated backs, though, because the flatter shape of the part makes it a natural for that method and mechanical clamping of a large, flat plate is more problematical than for sides.
 
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