Larson 551 side damage

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Larson 551 side damage

Postby Chris Vallillo » Sat Jan 27, 2018 1:44 pm

After years of working my way up the food chain of guitar repairs, I'm now working on a Mauer 551 built by the Larson Brothers (confirmed by Tony Klassen and Gruhn Guitars as the real thing). The biggest issue was a side split on the lower bass bout. I've been able to close and cleat the break but there is a small amount of damage that will need to be filled. Here are a couple pics. Please excuse the odd orientation, for some reason some of the images are rotating and I don't see how to change that.

IMG_7524.jpg
IMG_7524.jpg (36.33 KiB) Viewed 615 times
The neck coming off at New Era Guitars

IMG_7545.jpg
Side crack being glued and cleated

IMG_7547.jpg
Inside view

IMG_7550.jpg
Outside damage to repair

As you can see, there is a tiny bit of break out on the joint that will need to be filled plus the small holes for threading the guitar string holding the cleats in place. Since this guitar is worth more than anything I've worked on before, I want to make sure I do the repair correctly. I'd appreciate suggestions from forum members as to the best way to fill the gap. There are enough cleats to assure structural integrity, but I don't want the repair to be obvious or result in significant finish touch up. As recently suggested in another thread, the article in Fretboard Journal about repairing the early F5 talked about glue and saw dust. I've been told that could be difficult to stain and match color. I'm also considering a lacquer stick, but I have little experience with that method. And of course, there is always epoxy...

Comments and suggestions would be greatly appreciated!
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Re: Larson 551 side damage

Postby Barry Daniels » Sat Jan 27, 2018 1:56 pm

Sawdust and glue is never a good idea for a quality repair. Lacquer stick is good but it does require skill. I would not recommend epoxy fill because it would be hard to get level on a curved side and it looks like there are open areas in the crack that would allow the glue to fall through. A rosewood splint would be the best option from a color match and structural integrity standpoint but there would be lots of finish touch up required. No good answers for you but the wood splint is really the only way to do this.
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Re: Larson 551 side damage

Postby Chris Vallillo » Sat Jan 27, 2018 2:29 pm

Hmmm. Thanks Barry. I agree about epoxy and getting the patch level. Not sure about the splint, though. As you mention, I'll end up with significant finish damage and touch up. Is there a good reference/tutorial for dealing with the lacquer stick anywhere? This is the kind of repair I'll think about quite a while before attempting!
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Re: Larson 551 side damage

Postby Bob Gramann » Sat Jan 27, 2018 2:45 pm

You might make a mockup and practice doing the splint. It’s not likely to be invisible in the end, but it is a good, lasting repair.
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Re: Larson 551 side damage

Postby Barry Daniels » Sat Jan 27, 2018 5:40 pm

I don't think lacquer stick would be good for this repair as it will not stand up to any flexing. It is very brittle and if the sides move in the slightest, the lacquer will crack and possibly fall out. Like I said, the splint is the only way to repair this but this will be a challenging one. You probably should not do this one if you have never done one before.
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Re: Larson 551 side damage

Postby Clay Schaeffer » Sun Jan 28, 2018 12:04 pm

Mohawk makes epoxy putty sticks that could fill that small gap effectively. Top coating with powder stains and using lacquer or shellac (to pick up the yellow) as a binder you could match the rosewood color, and finally, using graining pens you could fill in the dark lines to "break up" the filled area and match the existing grain.
Mohawk makes a lot of materials for repairing and retouching furniture to make it appear as if it was never damaged. They do sell lacquer sticks for doing "burn ins" but those tend to be more brittle than the epoxy putty fills.
For a simple fill material that can be color matched fairly well and will absorb some stains - either sawdust and lacquer, or bondo can be used. Mohawk makes a wood colored bondo that can be colored with powder stains and will also absorb dye stains (as will regular auto body filler). Neither get as hard as the epoxy stick material.
Making inconspicuous repairs is a trade unto itself. It can take years to master it, but with a few simple products and a modicum of artistic talent people can make repairs that are not immediately obvious.
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Re: Larson 551 side damage

Postby Bob Gramann » Sun Jan 28, 2018 2:03 pm

It’s often really hard to redo a botched repair that was done with epoxy. A splint repair, done with hot hide glue, can be easily redone.
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Re: Larson 551 side damage

Postby Mark Swanson » Sun Jan 28, 2018 2:48 pm

Wood is of course a very good way to fix it, and it's just good to know that it's filled with real rosewood. On the other hand, a fill is a fill, right? What difference does it make what the fill is, if it isn't going to be wood? It would be hard to do with wood and make it look nice.
I know dust and glue isn't seen as a good thing, but I have managed to get pretty good at filling with dust and CA glue. I would fill this in the same way that I might fill a gap around an inlay. It sounds nasty I know...but, I would fill the gap with dust and coat it with CA. It would probably take a few times to bring it up to level, then scrape it back with a razor blade and after that is levelled and wetsanded smooth I'd coat the crack with a small brush and lacquer, to blend it in. After the right finish touch up, you would not be able to feel that and hardly see it.
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Re: Larson 551 side damage

Postby Chris Vallillo » Mon Jan 29, 2018 1:43 pm

Thanks for the advice, everyone. I've considered your opinions carefully and have concluded that the best solution in this case is a #20 amber superglue drop fill. The picture above makes the break look much larger than it really is (this is a Larson and the body depth is quite shallow compared to a modern day dreadnought). The break itself has been carefully glued and cleated. When I shine a light inside the guitar, I see very little coming through the crack... primarily through the pin holes used to draw the cleats in place. The issue here is the loss of some of the wood at the crack which had "crossed over" itself and broke off a bit of the outer edge in the process. It is structurally sound, the main issue is cosmetic. I've done dozens of splints in my time, primarily on the tops, but occasionally on a side, and this just does not rise the that level of that repair technique.

I've drop filled the area with amber superglue. As Mark suggested, it will take a couple applications to fill the pin holes. I'll scrape it back with Frank Ford's bent razor and tape technique and do a final touch up with french polish. Of course, this is not without it's risks... The razor scraping is a delicate process and one I have not fully mastered yet, but I'll take my time and work carefully.

Pics to follow.
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Re: Larson 551 side damage

Postby Barry Daniels » Mon Jan 29, 2018 10:36 pm

I have found that to turn an edge on a razor blade you have to use considerable force and several strokes. The key is to find some way to securely clamp the blade about an eighth of an inch from the cutting edge. This prevents the blade from flexing a bunch when you turn the burr. When you get a good burr you can really feel it drag when you scrape the blade over your finger tip.
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Re: Larson 551 side damage

Postby Chris Vallillo » Wed Jan 31, 2018 1:57 pm

Excellent advice! I've always had a tough time getting a good burr on the razor.
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Re: Larson 551 side damage

Postby Clay Schaeffer » Wed Jan 31, 2018 9:52 pm

Another tip on using a single edge razor blade as a scraper is to round the ends slightly with a piece of sandpaper. This helps to keep the ends from accidentally scratching the finish. Tape over the ends also works, but without it you can scrape a little closer to "flush" with the surface.
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Re: Larson 551 side damage

Postby Chris Vallillo » Thu Feb 01, 2018 6:39 pm

Well, the results are in.....

I used the taped razor method (though I'm going to remember that sanding the edges down trick!). Here's how it looked with everything leveled.

IMG_7583.jpg


This process worked very well although minor distortion in the wood caused some scraping beyond the immediate area. It leveled things out nicely though so I decided to go with it. The scratches in the finish are not through the varnish and will disappear with a light french polish touch up. Add in a bit of work with a detailing pen and it should blend in nicely with the wood grain.

Here's what it looks like with a quick swipe with of Naphtha.

IMG_7586.jpg
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Re: Larson 551 side damage

Postby Barry Daniels » Thu Feb 01, 2018 6:48 pm

Scotch tape is better than masking tape on the razor blade. It will totally prevent scratches like that.
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Re: Larson 551 side damage

Postby Chris Vallillo » Thu Feb 01, 2018 8:50 pm

Thanks for the heads up, Barry. That's one of the issues I had using the razor blade, it tends to cut through the masking tape very easily. I'll be sure to try that next time.
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Re: Larson 551 side damage

Postby Mark Swanson » Fri Feb 02, 2018 12:57 am

Good job!
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