Crushed place, upper bout, Larrivee parlor guitar

[dep]

First, thanks to Frank for starting this great place. I'm pretty sure that along with frets.com it will become one of my favorites.

I almost entirely mess around with banjos and am not hugely experienced at that. Now I've been given a project that looks to have one chance to get it right, and I defer to those who have experience in figuring out how to proceed.

As the picture shows -- presuming I attached it correctly -- this little Larrivee got whacked by something, leaving a crushed-in area in the upper bout. The break is about 3/4x 2 1/2 inches. I have not touched it.

The question, of course, is: How do I fix it? I can get to the break from the inside and push it back. I'm wondering if I should wet the wood, maybe put it under magnifying glass and try to pick up the individual fibers with a dental pick, and glue it with -- what? -- or if there's some more sensible way of proceeding. I'm presuming that it is not going to be cosmetically very nice no matter what I do.

Kind of hoping that this sort of thing is so common that there's a quick-and-easy fix.

Another question: is wood this thin typical of inexpensive guitars?

Many thanks in advance.

[hobocaster]

Hi,

If you are able to fit it back together and glue it up.. rather than shot bags, you might try making cauls out of Friendly Plastic, or something like that. I have no personal experience with this type of product, but this seems like it might be a good place to use it. Potentially you could mold some of this goop against the same spots of the upper bout on the opposite side of the instrument (with a layer of plastic wrap in between). Assuming the curve on this side is nearly indentical to the other, when the stuff hardens you'll have an inner and outer caul, perfectly conformed to the spot you want to glue up. Line it with cork and plastic wrap, and glue away!
This is just theory of course, like i said, I've never tried the stuff myself. Ol' Mr. Ford has written about using similar molded cauls on frets.com . They sell Friendly Plastic at stew-mac.

[Jim Bancroft]

If you can push and piece things back together you don't any sort of caul. Actually a caul may cause problems, like you are planning on using. The only caul I would use, if it was needed, would be one cut from wood that matches the curvature of the side, waxed or wax paper will need to be used to keep it from adhering to the side. Then you need a way to clamp it.

Like I said, I think it can be done without the use of a caul.

Jim

[dep]

We have a result. It's better than I feared but not as good as i hoped. Having glued the support patch inside and worked the original wood to conform, i sanded and leveled it best I could, as in the previous picture. To match colors, I got three concentrated pigments from Stew-Mac (old amber, red mahogany, medium brown, not needing, it turns out, the last one) and diluted them considerably, applying the resulting water-based stain with a q-tip. The stain was very, very diluted, so it took about 50 coats, but matched pretty closely (what didn't was the grain filler, which went dark).

Then numerous light coats of water-based urethane, the first with a drop of red mahogany pigment to use in blending. This was followed by wet sanding.

The result is in the attached picture. The repair cannot be felt, despite how it looks. But given the damage originally, I think it's non-awful.

Thanks everyone for your help, without which the repair would not have been successful at all.

[Jim Bancroft]

The results look good to me considering the original damage.
Did you use a clear grain filler? On the water base stains I always use them straight out of the bottle, and only one or two coats are needed.
Once I get the color right, I apply a coat of shellac, then maybe a clear grain filler, or you can just apply a number of coats of shellac which will be the grain filler and it won't change the color, level, then put on whatever final finish you want.
Congratulations
Jim

[dep]

I used a purported mahogany grain filler. Then many coats of the urethane, figuring that I could take it down to level, which worked. But I'd use your method in future -- the match would have been much nicer.

[danove]

Provided you plan to end up with a shim reinforcing at the inside,
you may use this shim to tighten up the pieces back in place.

Drill a small hole in the middle of the bash and in the middle of the shim.
Thread thin steel wire from outside, through the middle of the shim,
through a ruler and lock it.

Add hide glue and tighten it all in place from the outside.

I use a violin peg for this, with a home made support and a lock.
Good to have a few in the toolbox.

For shim, use a few layers of straight, but thin and flexible veneer.
The glueing decides how many layers will stay.....

[hobocaster]

I agree with danove and his technique.

And you're right Jim, probably no cauls are needed, and the clamping would be awkward. I was responding to the use of shotbags, and brainstorming outloud (actually i was quietly typing) along those lines. After thinking and reading further, it seems that danove's idea would be a good approach. I've used a similar technique as this for more minor crack repairs that were hard to align.

By the way.. Hi, I'm new to this forum, and fairly new to the luthierie world. This and frets.com are great resources! I often encounter challenges where I try and think up my best solution, and then get online to see "what would frank do?" If I chime in with a silly idea, feel free to counter me and tell me it's silly. That's part of the learning process!

[Rev George]

I think danove has the best idea. Dude! that is an ugly hole! Glad nobody brought that to me. I think that if you get it back together and it holds the customer should be way happy! That's a bad one. Let us know how it turns out.

Rev George

[dep]

if you look a few messages up, i've posted a picture of how it turned out. would have liked it to be closer to invisible, but at least i think the repair is sound. about to string it up right now.

and again, thanks, everybody, for all your help. it was essential.