Wilborn Guitar Attempt

[saltytri]

Nice project! Using Ben Wilborn's work as a guide seems like an excellent idea. Here are a few tips that have been helpful to me. I've built dozens of tenor and baritone ukuleles with laminated sides and backs (tops also, but that's its own story!). Red Titebond works great. I tried three layers at first, and have decided that two layers provide all the strength and rigidity that are necessary. I doubt that you need an inner layer with the grain at 90° from the inner and outer. As long as the longitudinal grain on the two layers is somewhat skewed rather than parallel, it's not likely that the sides will split. I do this also on my laminated backs, which are two layers with the inner layer skewed from the centerline at just a few degrees. Between this and the few thousandths of extra thickness that result from using two layers, the backs are not easy to break and are more than adequately stiff without any lateral bracing. The two layers are glued in a radius dish mold under vacuum pressure and hold their shape perfectly over time. It is necessary to use epoxy rather than Titebond on the backs because its water content will make the panels potato chip every time, no matter how long they stay in the mold. More info and photos at onoukes.com in the "Blog" section.

[scamp]

I doubt that you need an inner layer with the grain at 90° from the inner and outer. As long as the longitudinal grain on the two layers is somewhat skewed rather than parallel, it's not likely that the sides will split. I do this also on my laminated backs, which are two layers with the inner layer skewed from the centerline at just a few degrees.

I agree with your input. Unfortunately, this has turned into somewhat of a technical challenge which I am having a hard time letting go of. I'll probably do as you suggest but I just have a few more things I want to try.

Good to hear that Titebond Original ( "red" ) works laminating the sides. This is what Bogdanovich does. I was planning on using epoxy as I have had bad experiences with water based glues and thin veneers. Sounds like it doesn't work well for the back for some reason. Maybe it's a bigger area??

As far as two vs three layers, Ben has informed me that it isn't just the issue of strength, although that is probably the most important reason. It turns out that Ben picks the depth of his bindings to match the depth of the middle layer / inside layer interface. So in his case, the outside layer is 0.06 and the middle layer is 0.03 so the depth of his bindings is 0.09. He claims when he routs to this depth he can just scrape off some of the glue and the depth is more of less perfect. Anyway.... just an FYI.

[saltytri]

Ben makes an interesting point. Thanks for that and for your own insights! By the way, I also got going on laminated sides after reading the Bogdanovich book, along with Gore.

I think the reason to avoid any water-based glue on the back is that a back is really almost flat and doesn't have enough compound curve, or "dish", to resist deformation by the glue as it loses water content. The reason Titebond doesn't create a warping problem on sides is that even though the bends are only in one plane, they are pretty tight radius, which keeps a side from bending in the top-to-back direction.

As far as the shape of the body as seen from above is concerned, my experience has been the same as yours: the bends remain very close to the shape of the mold that they are formed on. Excursions from the perfect curves are very minor and get straightened out by the solid linings, which are also laminated to the correct curves to fit nicely onto the inside surfaces of the sides.

I thought at first that the tight bends on a uke would make it necessary use three layers to preserve the correct curves but this just isn't so.

Having said all that, I'd consider using epoxy on sides if it weren't a little nasty as compared to Titebond!

[scamp]

I've read the same things about laminated sides ( Trevor Gore, Bogdanovich etc.) I have seen quite a few people switching to this technique.

BTW... I saw a video from an Italian luthier who minimizes the cupping/distortion when using Titebond original on veneer by wetting the opposite side of the veneer ( the side not being glued ) with water. It appears the water gets soaked up on both sides equally so the veneer doesn't warp. I've tried it and it seems to work but I'm still a bit afraid of doing this on laminated sides etc.

[scamp]

Finally success making the maple cross grain laminated guitar middle layers !!

It turns out, for some reason, the hard maple I was using in my previous attempts was really stiff across the grain.
Hence, when you thinned it out to 0.03 inches and tried to fit it into the side mold the glue joints would break in the areas where there was significant curvatures. To make things worse, since the hard maple board I used to make the cross grain pieces was only 3 inches wide there was a glue joint every 3 inches.

So..... I just happen to find some hard maple veneer ( 1/16 inch thick ) what was more or less quartersawn and 7.5 inches wide against the grain and 24 inches long with the grain at my local Woodcraft store. Cut it up into 5 X 7.5 inch pieces, sanded the joints perfectly flat ( candled them ), carefully glued them using CA glue and thinned them down to 0.03 inches. ( see pictures... BTW... I use a 1/4 inch thick MDF board with 120 grit sandpaper glued to it as a sanding base when trying to sand this thin. Otherwise the sanding drum sometimes hits the belt where there is a seam that pushes it up a bit and it messes up the sandpaper on the drum )

Middle Layer Maple Veneer Method 1.JPEG

Thinned Side.JPEG

What was interesting was the new thinned maple was much floppier than the other old maple I was using. Checked the density of the new maple and it was the same as the other maple I was using and consistent with hard maple. To see if it would work I laid the new maple side into the mold and it fit perfectly with little stress on the glue joints etc. I don't see a problem so I'm happy. Still don't understand the big difference in "hard maple" but there definitely is. Onward!

Side in Mold.JPEG

Middle Layer in Mold .JPEG

[saltytri]

Another trick is to put the glue on evenly and to use just enough. I squeeze it on from the bottle and then spread it evenly with a 3" wide paint roller of the type that is commonly available at paint outlets. The ones I'm using now com from Home Depot. They fit a standard 3' roller frame and the foam is about 1/8" thick. They come in the usual 9" format and can easily be cut into thirds. They are reusable many times because the roller tube is made of plastic and the foam is securely glued to tube, so they can be rinsed clean with warm water under a tap.

[saltytri]

Another trick is to put the glue on evenly and to use just enough. I squeeze it on both surfaces of the wood the wood from the plastic bottle and then spread it evenly with a 3" wide paint roller of the type that is commonly available at paint outlets. The ones I'm using now com from Home Depot. They fit a standard 3" roller frame and the foam is about 1/8" thick. They come in the usual 9" format and can easily be cut into thirds with a saw. They are reusable many times because the roller tube is made of plastic and the foam is securely glued to tube, so they can be rinsed clean with warm water under a tap.

[scamp]

Decided to move on the neck.
As usual for this guitar, it is a bit of a challenge.

The neck for this guitar is difficult and unique for two reasons.

One reason is, unlike a traditional guitar where the neck extension on the guitar top is only the fret board, in this case part of the mahogany neck actually sits on top of the sound board ( about 0.5 inches thick ). So instead of the strings coming into the saddle at a - 1.5 degree angle they come in at a + 1.5 degrees. This presents an issue with how you attach the neck heel since the heel isn't at the very end of the mahogany neck. because of this it really only makes sense to do a scarf joint/stacked heal design.

The other reason is because this is a multiscale guitar, the nut isn't perpendicular to the neck. It actually is at an angle. As a result, the headstock plain needs to be tilted at a slight angle relative to the fingerboard plain so the angle where the fret plain intersects the headstock plain is at the correct angle ( about 8.5 degrees off of perpendicular.

So... to do this I did a conventional scarf joint neck leaving a little extra thickness on on the headstock of about 2 mm. Once I had this, I sanded the headstock surface at a slight tilt by hand until I got the right 8.5 degree angle at the nut location. I then used a spindle sander with fence attached to sand the back of the headstock to make it a uniform 12 mm thickness and also make a smooth transition into the neck.

Worked well Pictures below.

Scarf Joint Cut with Jig.JPEG

Scarf Joint Glue.JPEG

Scarf Joint Angle.JPEG

Scarf Joint Sand Back.JPEG

Scaf Joint Done.JPEG

[scamp]

Neck.JPEG

[scamp]

Decided to make the rest of the non-curved braces for the front and back.
Used Engelmann spruce for the bracing wood ( not as dense as Sitka but relatively strong )
All bracing is 1/4 inch.
Cut 1 inch thick boards into strips and thinned them down to 1/4 inch thick using drum sander.
Rough cut the braces to approximate lengths ( on the long side ).
Made a 28 ft and 15 ft radius sanding jig to put accurate radiuses perpendicular to the sides of the braces. ( copy of one that was sold by LMI ).
Used a plane to rough in the curves and then the jig to sand them down the rest of the way.

Pictures below. There are a total of 4 back braces ( not including the center strip ) and 12 front braces.
Will put them away for now until I complete the back and top so I can more accurately cut the lengths and trim them down to appropriate height.

Trim Braces with Plain.JPEG

Sanding Braces Curve.JPEG

Back Braces.JPEG

Front Braces.JPEG