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As Miss Emily Litella used to say, "If it's not one thing, it's another." I've been struggling with a side purling fix and just when I thought I had everything worked out, I find that my repeated sanding has left a portion of the sides too thin. So thin, in fact, that they flex pretty dramatically under finger pressure. The problem areas are in the relatively flat sections where the waist leads into the curve of the upper bout. I've been telling myself that reinforcement such as one would provide beneath a sound port might be an acceptable fix, but I'm skeptical. Advice and opinions would be greatly appreciated.

Thanks,

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George :-)

Honestly, sometimes starting over is the only option.... There would not be an easy fix for this IMO. You could remove the back and top to salvage as well as the head and tail block....

You want a new guitar, not a new frankenstein....

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I agree, assuming this is not a commission or a piece to be sold. If it's something you're making for yourself, it could be a useful experience to see if you can fix the problem. Good luck.

Thanks for the responses. I just build for fun, so I'll definitely be experimenting before throwing in the towel. Never put a laminate together. I'll do a search here to see what I can dig up. Any ideas or pointers would be welcomed.

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George :-)

Many older martins were as thin as .060 . As Fillipo states the laminate will add a great deal of support and it doesn;t need to be very thick to do this.

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As John said, many of the older guitars had thin sides. Adding wood veneer in the fashion of side tapes would probably provide plenty of reinforcement. What is the wood species and the model of the guitar?

Thanks to all. I found a couple of old threads discussing laminating sides for sound port reinforcement. Lot's of lovely work and great ideas. There does seem to be some conflicting opinion about laminating cross-grain or not. It looks like a majority are applying their laminates oriented parallel with the grain of the sides. Further discussion on this issue would be helpful. I'm not going to open a port, so might just go with a thin single ply.

Filippo - Yes, the box is closed, so thanks for the tips on making cauls.

Clay - The guitar is based on the Grellier L-00 plans and has mahogany back and sides.

This is only my third guitar and as yet I've not managed to complete one without encountering some kind of interesting obstacle; always the result of my inexperience. While building my first this frustrated me to no end, but I've since developed a greater level of patience and humility. Now I try to embrace the puzzle-solving aspects of these challenges--and hope that I don't make the same mistakes twice! It's all part of my education. Hopefully I'll soon be able to construct a guitar without running into unexpected surprises. We shall see.

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George :-)

You could try some fiberglass. Cut the glass to exact size, then wet out the wood area where it will be applied with epoxy, then apply the glass into position, smooth it out with an acid brush, and leave it to cure.

OK, so some people just can't handle fiberglass without making a bigger mess. I understand, so this may not be a viable solution. But if you can, this is a very viable solution.

If you do consider it an option, practice the procedure on some scrap first.

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What was the side thickness prior to bending and exactly how were you sanding? Machine? Hand? what grit? Plenty of Guitar sides will flex alarmingly at the point you mention.

Douglas - I saw your use of fiberglass in one of the sound port threads. Pretty slick. I like the idea and plan to experiment a bit with that in the future. I'm going to try to keep to wood on this one, at least for now.

Michael - The sides were 5/64" before closing the box. Thanks to my inexperience with pore filling, staining, and finish prep, they have now been scraped and sanded four times (220, 320, and 400 grits). The third time revealed an issue with my side purfling, which sent me back to the router and square one as far as preparing the sides for finishing. Yesterday, with new binding and side purfling in place and while doing my final sanding at 600 grit, I noticed the weak areas. I've compared the amount of flex to other guitars (completed instruments and one awaiting binding installation) and everything seems stout enough around the rest of the guitar, but in this one area there is too much give--at lest for my comfort level. The good news is that my scraping and sanding techniques are getting pretty good.

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George :-)

Those Grits won't have done much in the way of thinning the rib excessively. Scraper is another matter though. . . .

As Filippo said, you don't want to blow out the other side with too much internal clamping pressure.
If I were doing this, I'd probably try to put the body back into the mold first. If the neck is attached, I'd try to devise a temporary partial mold to support the area where the turnbuckle pressure will be applied. I'm not an experienced repair guy, but these precautions seem very prudent to me.

Please follow up and let us know how this goes for you. Many people will learn from this....and I will be among them. And if it doesn't work to your satisfaction, don't give up. Just chime back in. Lots of useful ideas are given freely by these excellent builders.

Thanks for the feedback. No neck on the guitar yet, so that will make things easier. Compared to some of you guys I work in geologic time. Don't hold your breath, but I will definitely report back.

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George :-)