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 Post subject: Bending veneered sides
PostPosted: Mon Apr 11, 2022 4:51 pm 
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Koa
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Location: Goodrich, MI
First name: Ken
Last Name: Nagy
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I'm building a tiny, Uke sized baroque guitar in A. I'm moving the strings over, and making it an 8 string, tuned like a uke. It will have about the same tension as a regular baroque, and a tenor 8 string ukulele. It is built with a body completely of spruce, and is veneered on the sides and back. So, the ribs have to be veneered. I have some figured Mahogany that should look crazy.

Now the question. What glue would you use? I was thinking CA. Has anyone done this?

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PostPosted: Mon Apr 11, 2022 6:09 pm 
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Brazilian Rosewood
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When I mold sides out of veneer I use West System epoxy. I warm the veneers to dry them out and then apply the glue which sinks into the veneer and makes it pliable I place it between wax paper and clamp it in the mold. I leave it in the mold a few days until the epoxy is cured (not just "set"). This seems to give the best results for flat stabile sides.


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PostPosted: Tue Apr 12, 2022 1:21 am 
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First name: Tim
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I have done it with polyurethane glue, gluing walnut veneer to walnut sides first using planks as cauls, and then bending the sides in a bender.

When I built my second guitar, using a thickness sander for the first time, I discovered--as so many others have--how easy it is to over-thin sides. Rather than discard the sides, I decided to try to glue walnut veneer to them, which would make them just thick enough. In some tests beforehand, Titebond original delaminated, fish glue almost held well enough, and PU glue seemed to work perfectly. I went ahead and used PU glue to laminate the veneer to the sides, bent them, and it all worked out.

PU seems to be an excellent glue, but I tend to avoid it because it has a short shelf life. But if you need a glue that makes a strong, permanent bond, and holds up to heat, it's a good choice.

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PostPosted: Tue Apr 12, 2022 5:49 am 
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Brazilian Rosewood
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I have an old parlor guitar that has rosewood laminated over spruce. Because of it's age i believe it was glued with hot hide glue. It's still stuck over 100 years later. I don't know how it was done (before or after bending) but if you have some scrap it might be worth a few experiments.


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PostPosted: Tue Apr 12, 2022 1:44 pm 
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Koa
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Clay, I think lamination would be fine, but it is probably over a hundred pieces a side! Besides that, I've never had a form or mold; I just bend on an iron. This will be the first build on belly. I think that way might work really well. I do believe that the originals were probably with HHG. But is there a technique? Urea or something to make it less likely to come apart with heat?

Tim, I've never heard of PU glue. Waterproof. And it worked for bending sides!

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PostPosted: Wed Apr 13, 2022 10:03 am 
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Brazilian Rosewood
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Ken, I've been following this thread and would love to give you advice as I have built many laminated sides. But I can't figure out what you are trying to do.


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PostPosted: Wed Apr 13, 2022 10:42 am 
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Koa
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Barry,

It is from plans for Voboam baroque guitars. Many were very ornate, others were more simple. The ornate ones were veneer over spruce. Here is an example. You can see that the one I am doing is different. The long strips are what I'm using to cut the diamonds and triangles out of. The patchwork idea wasn't working.

The plans have many different styles of inlay, veneer, glue ups of black and white wood, headstock and neck treatments, and rosettes. It was the bling of the day!

So it is gluing veneer on, and then bending the ribs.

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PostPosted: Wed Apr 13, 2022 11:29 am 
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Brazilian Rosewood
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I have never tried anything like that so anything I say should be taken with a grain of salt. Titebond II or III is used by many builders to hold laminated binding together during bending but this is usually in a Fox Bender with metal blankets sandwiching the layups. Bending on a pipe would result in your triangles coming apart. Without forms and a bender, I don't see this ever working.


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PostPosted: Fri Apr 15, 2022 5:35 pm 
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Koa
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Well, I'm going ahead with the HHG. They did it 400 years ago, with HHG, casein, or maybe fish glue. The spruce backing is about a mm thick. The veneer is about that now. After it is glued up, I'll trim it down to 1.5 or so. I think I'll glue a strip of.Limon on the top, with paper over.that.

I've learned a whole lot about how to to this. Nothing like jumping in.and getting your feet wet.

Cut the strips.The same.as.the panel.

Mark each piece with a number so they don't.get mixed up.

Wet the bottom of the side where you're gluing, so it doesn't bend.

Glue three pieces on a diagonal, so they fit tight.

Have a pack of spare Xacto blades.

I have one side almost done, 50 panels, and 50 thin black lines. It will need some touchup. I'll bend that one first! That way, I can mess up the beginner side if I have problems. If it bends fine, I can use it, or make another depending on how it works.

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Last edited by Ken Nagy on Sat Apr 16, 2022 8:20 am, edited 1 time in total.

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PostPosted: Fri Apr 15, 2022 10:00 pm 
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Koa
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not that I know squat about how that piece of history was made, but I'm thinking that the veneer was softened up, pressed into a curve, left to dry, THEN glued to a solid heat bent side...

veneers were developed a LONG time ago as a way of dealing with limited supplies of wood...it further progressed into a work of art with matching/contrasting/different species put to use in patterns...by the time that baroque guitar was made craftsmen had a pretty good grasp of techniques to get pretty thin pieces of veneer


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PostPosted: Tue Apr 19, 2022 3:29 pm 
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Koa
Koa

Joined: Sat Mar 09, 2019 4:50 pm
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Location: Goodrich, MI
First name: Ken
Last Name: Nagy
City: Goodrich
State: MI
Focus: Build
Status: Amateur
AHHH!

Ever have an epiphany about a process, when you were about done? I just did. One of those ones that make you feel like Steve Urkel. "Did I do that?

The veneer would have been EASY if I did it the right way! Glue the veneer on, IN ONE PIECE!

Then you can cut thin slots for the blacks. A couple knife cuts. A thin sharpened file. Simple.

If I ever do a big one, that's what I'll do.

Oh well. Now I know.

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