2 piece walnut body, separating at each end a bit

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Phil Donovan
Posts: 7
Joined: Tue May 01, 2012 10:11 pm

2 piece walnut body, separating at each end a bit

Post by Phil Donovan »

Hello, its been a while and very nice to be back!

I may have rushed into this "fix" but here it goes.

A 2-piece walnut body that I began many years ago started to separate at the top and bottom. It didn't occur to me that an unfinished body would have done this over time. What I did as a way to hopefully recouple the wood at the top and bottom of the body was to use a 1" Forstner bit to 1.) drill a hole through the neck pocket, front to back. And 2, come up through the bottom of the body about 2.5 inches.

My theory was that filling these holes with a piece of 1" Walnut dowel section would reconnect or recouple the wood where it had gradually began to separate over time. One of the things that drove me to do this was that when the guitar was originally shaped (a Stratocaster body shape more of less) it had a very distinct and resonant tap tone. After inspecting it after a couple of years of sitting, the tap tone seemed to be much less resounding and distinct. I had to wonder if the body had lost some it its original resonance do to the separation of the 2 sections. I should have checked with the experts first before doing this but, here it is.

Now that I've done this, I'm willing to go forward with filling the holes with the walnut dowel but, 2 concerns. It makes good sense that I won't want to use a glue that will expand, or a glue that caused the wood to expand for risk of pushing the 2 pieces apart, causing further problems. I was hoping some of you folks could offer me solution that would give a strong bond between the separating ends, and do so with out swelling or expanding. Am I on the right track here? I have heard that epoxy is the least likely to expand so, without any advice, that is probably the way I would go for good or bad. I liked the idea of hide glue also as its been toted to pull wood together while drying. But, that may depend on how well the surfaces meet. And I have no idea just how well that will happen. I can't say for sure how straight or even the forstner bit traveled as it made the hole, especially the longer one at the bottom of the guitar.

Any feedback will be very welcomed here. I'm really curious to know how some of you might go forward. I'd really like to get this project nearing to the finished side soon!

Thank you all so much.

Phil Donovan
Gordon Bellerose
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Joined: Wed May 30, 2012 11:47 pm
Location: Edmonton AB. Canada

Re: 2 piece walnut body, separating at each end a bit

Post by Gordon Bellerose »

Pictures would be really nice. I'm always interested in how others do repairs.
I need your help. I can't possibly make all the mistakes myself!
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Peter Wilcox
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Location: Northeastern California

Re: 2 piece walnut body, separating at each end a bit

Post by Peter Wilcox »

Can you post pictures of the problem, and the holes you've made? It's not clear to me.

Edit: LOL Gordon, beat me by a minute.
Maybe I can't fix it, but I can fix it so no one can fix it
Eric Baack
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Joined: Thu Dec 27, 2012 4:28 pm

Re: 2 piece walnut body, separating at each end a bit

Post by Eric Baack »

What glue was used originally?
Chris Richards
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Re: 2 piece walnut body, separating at each end a bit

Post by Chris Richards »

Did the body have any finish on it when it was left for the couple of years?.... I'm suspecting that the wood has taken in a bit of moisture and expanded a tad and that's why the tap tone has changed...Drying it out a bit may have bought the joint back together or somehow getting some Titebond into the separation and re clamping may have worked since the Titebond may expand the wood a little or you could have tried the above and put some water on those areas? I'm sure your dowels will make a solid repair it's just a shame to drill holes in your work...
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Barry Daniels
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Location: The Woodlands, Texas

Re: 2 piece walnut body, separating at each end a bit

Post by Barry Daniels »

I would have sawn the body down the joint, planed the joint and reglued.
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Eric Baack
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Joined: Thu Dec 27, 2012 4:28 pm

Re: 2 piece walnut body, separating at each end a bit

Post by Eric Baack »

Barry Daniels wrote:I would have sawn the body down the joint, planed the joint and reglued.
This
Mark Fogleman
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Joined: Sat Apr 27, 2013 10:02 pm

Re: 2 piece walnut body, separating at each end a bit

Post by Mark Fogleman »

One thing about thick boards is they are never really "dry" in the middle when the outside 4-6 mms are crispy dry...even after decades of being in a dry environment. Wood joints separate d/t the forces on the joint from wood movement that can be from drying, slight gaps in the joint we try to correct with high pressure from clamps when we initially glue up the joint and/or glue starvation from excessive clamp pressure. Over time, wood wants to move and any joint weaker than the surrounding wood loses the battle. Here's what I would do:

Neck Pocket Split
The best fix for this would've been to rout a bow tie mortise ~1/2-3/4" into the pocket (under the neck extension) crosswise to the grain of the body and glue in a bow tie plug with the grain running lengthwise. This would lock the joint, prevent future separation and not be seen from the outside of the guitar once assembled. A dowel going front to back is a cross grain joint and has much weaker grip to prevent future separation. Since you have 1" hole there, I would fill it as you planned but make it a feature from the outside with an inlaid 1" section of a metal ring (cross section of Aluminium or Copper pipe?) into the ID of the hole and a contrasting wooden plug (Maple dowel section?) with an Abalone shell fret dot or something inlaid in the center. Then rout a bow tie mortise into the neck pocket as above and insert a mating bow tie plug.

Tail Split
Insert a plug into the 1 ' hole and maybe make it a feature (Maple) since it will be seen or plan to use a tailpiece to cover the repair. It's a long grain glue joint and should be strong.

Glue
Epoxy, Titebond, CA, PU glues are a one shot deal for fixing the split. If the split comes back, it's impossible to get it back to raw wood to re-glue it. I would just wait to fill the gap until the finishing stage and maybe fill with hot hide glue (not the kind in a bottle...it's flexible d/t Urea added) by sticking a piece of masking tape to the narrowest side of the crack and pushing it into the crack. Don't try to close the gap with a "Hercules" clamp. It'll just come back. Use epoxy for the dowels, bow ties and various bling you add.

Taptone:
The best sounding acoustic guitar I have ever built had Mahogany back and sides that tapped like a piece of wet cardboard. Taptone of a guitar body is way overrated as an indicator of future tone quality. What microscopically small amount of difference you could make now would not be able to be discerned in a blind A vs B comparison.
Gordon Bellerose
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Joined: Wed May 30, 2012 11:47 pm
Location: Edmonton AB. Canada

Re: 2 piece walnut body, separating at each end a bit

Post by Gordon Bellerose »

As Barry said above, sawing it down the center line and re-gluing may have been a good option.
I have done this before, and the things that are affected by the thickness of the cut, are the neck pocket, pickup routs, and bridge holes, if they have been drilled.
I compensated by cutting out 1/2 inch on each side, and added a piece of 1 inch maple down the center.
I had to re-rout everything, and drill new holes but it worked.
I need your help. I can't possibly make all the mistakes myself!
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