Official Luthiers Forum!

Hi,
I'm relatively new to the forum and to building guitars. As I'm just about to finish my first kit (pics posted upon completion), my attention will soon turn to re-gluing some loose kerfing on an old guitar that I have and I thought I'd ask here for some advice before proceeding.

The guitar in question is an old Gibson LG-2 with A LOT of mojo working. It has several rather obvious repairs and bumps, bruises, nicks and dings galore, so I'm not worried about working on the instrument myself.

The guitar is solid structurally, save for about a 2" span of kerfing along the treble edge of the lower bout. My thought is to run some tubing out of a syringe, squirt a little glue in there and clamp it together with some cauls and magnets. Thoughts, better ideas, cautionary tales, etc. are all welcomed.

One other thing I've noticed about the guitar is that the old squeeze out visible inside the body appears to be completely opaque and a kind of mocha brown color. Obviously I'm not an expert at this, but the glue looks kind of unusual to me. Anything I need to know about this? Again, your thoughts would be welcomed.

Thanks,
George

_________________
George :-)

Sorry but for Howard's sake I have to say this!! what is loose is the lining!!! kerfing is the voids in the lining that inable it to bend easy. kerfed lining is lining that has kerfs cut into it. kerfling is the sawdust on the floor left behind by cutting the kerfs into the lining ( Sorry this is a long standing joke arond here)

I assume the lining is loose from the rim and not the top or back. How much gap is there between the rim and the lining? Does it push back easily? if minimal and yes are answers then your plan sound reasonable.

Dang! I hate it when I'm a long standing joke.

The lining seems to be loose from both the top and sides. The gap is minimal and the lining can be pushed into place easily.

Thanks for the clarification and advice.

George

_________________
George :-)

Sorry I did not mean it as a criticism just a joke that we never will let die kind of lie when I capitalize the P in French Polish and get asked if I also offer German Irish finishes

Now to the task at hand. Still think you on track but will say if the lining is loose fron both then the guitar has been likely exposed to very dry or very hot conditions for an extended time frame. look close for other seperation issues.

Hey George--

Welcome to the OLF! The glue syringe will work well. Rare earth magnets will also work well as clamps. Cauls can be made many ways, sometimes its just as easy to carve a little piece of wood that fits the profile on one side and then glue a magnet on the other. You'll also want some aluminum foil or waxed paper as a bond breaker. I'm sure others will be chiming in with more idea's. Best of luck on getting the old guitar back to being a player!

_________________
Jim Howell
Charlotte, NC

Thanks for the replies. I figured this glue failure might be the result of heat or dryness. There isn't any other damage that I've identified, but, as I said above, it's pretty scruffy. I like to think the scars are there because the guitar's superior tone has resulted in it being played more than usual. I'll be going over the guitar very carefully many times in the days ahead. Hopefully I won't find any additional problems.

No worries. All razzing taken in good spirit.

George

_________________
George :-)

Three thoughts off the top of my head: First, I wonder if it would be easier to get in there with a palette knife rather than your syringe/tubing idea. Second, it might be best to use epoxy if the gluing surfaces seem contaminated and/or will not mate tightly when clamped. Epoxy (esp thickened) fills gaps much better then other glues and will likely bond better to a lot of crap that might be in there. Finally, I might consider cutting the loose lining away from the rest of the lining and taking it right out of there. I'm not sure I would do that; it's just an idea. It would allow you to clean up the gluing surfaces of the top and sides, as well as the lining itself, then glue it back in.

The brown glue you describe might be epoxy with a thickener that gave it that color.

A lot depends on what the historical/vintage/collectible value of the guitar is. If it would potentially have a high value if properly restored, I would, if it were mine, give the job to someone qualified to do that, because I am not (yet).

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd,
Good ideas. I was wondering if cutting the loose lining out and then replacing it would be a good solution. I'll know more once I get in there and give things a closer inspection. The guitar is somewhat valuable, but it is in pretty rough shape. I'm confident that anything I do will be better than what's been done before. It if were in collectible condition I wouldn't be contemplating this repair. I'll keep that in mind as I decide how to proceed.
Thanks for sharing your thoughts,
George

_________________
George :-)

Are you saying that the lining (or I'm actually fine with calling it kerfing ) is loose from both the top and side for a short span, though the top and side are still together? Did you fit a feeler gauge in there to see how far it's loose, or is in notably loose and movable? That's a bit odd....

For odd interior glue jobs I made a glue injector with a butterfly needle some time back. Here's a thread with it from some time ago.

http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=9954&p=136445

As to the opaque off-white or perhaps "light mocha" colored glue, I'm not entirely sure but I believe it's casein glue. I've not seen any other notes or mention of it before, but I've been keeping loose notes on it for a few years. Gibson used it for many years, only on the side/kerfing joint. The earliest occurrence I've found could arguably been from very early '33, or possibly even late '32. though hide glue still seems to be the norm until months later. My best estimate so far is mid to late 1933 when it came in to standard use and seems fully transitioned by the beginning of '34. There are still a few isolated occurrences I've found that seem to be out of this range which I can't fully explain though. Of course verifying dates from this era with any certainty can be a challenge, which is largely the reason I'm trying to narrow this down to use as another dating tool.

This is the only photo I have on hand right now, from and early Kalamazoo with solid lining. I could probably get some others of kerfing this afternoon if you like. It's usually fairly light cream colored, though may get a tad darker on some.



In any case, the glue is usually quite reliable, and I've very rarely seen any failed joints. They still used hide glue on the lining to top and backs, and only used this adhesive on the lining/side joint that I can find.

If your "mocha brown" description refers to something notably darker, perhaps with a bit of an orange hue, then it could be the RF-cured glues they used for a while in the late 40's / early 50's. That stuff is terrible, and just crystalizes and falls apart with time. I don't recall them using it on kerfing/side joints, though you may see it on some top or back to side/kerfing joints (usually archtops).

Sorry to ramble so much about glue, but I probably spend a bit too much time thinking about it.

_________________
Eschew obfuscation, espouse elucidation.

It's pretty unusual for the kerfing to come loose for a couple of inches without any visible injury on the outside. Loose from which surface, and how do you know it's loose?

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

David,
Ramble on! And thanks for the detailed information. I don't have the guitar in front of me, but the color in your photo seems about right. I'll try to get a good shot of mine and post it for a comparison. I've been told this guitar was built in '58, which may not add much of value to your database. I've read where some people don't think much of these after '55. I don't why that is, but I've been looking at these and L-00 models off an on for years and have to say that this one sounds great and the action on it is as sweet as any guitar I've ever played.

Here's a picture:



As fate would have it, the loose section is deep enough inside the guitar that I can't get my arm far enough in to touch the lining with my fingers. (Just a tad to the right of the treble side leg of the guitar stand in the picture.) However, it moved pretty freely when I pressed a thin dowel against it, which leads me to believe that it has let go from both the top and side. I have not detected any other separation. I'll have time this evening for a more definitive examination.

Thanks again,
George

_________________
George :-)

I'll apologize in advance for the temperature/colour of the pictures. My wife has the better camera this week, this one doesn't work well with my lamps, and I can't seem to recover any natural tones.

Anyway, here's a '38 L-5 with casein (at least that's what I've been calling it - not 100% sure), and hide on the top/back joints.



Then here's a '64 ES-335, by which point they seem to have switched to a PVA (can't really tell from my bad photo though) on the kerfing/side joint, and that RF-cured whatever-it-was adhesive on the top and back plates. It should have a very reddish, rusty hue to it, sometimes seeming more orange as it crystalizes and starts to crumble.



I'm not sure exactly when the later changes took place, or how it differed on models - I haven't taken many notes on this feature past the mid 40's.

More to the point though, Howard is right. Unless it took an impact, that would be a very strange area to come loose. If everything is holding together fine and it is just loose at the edge, it may not be a problem worth going after. In fact, Gibsons were like this in many places original from the factory and have held up just fine. I should have take shots of another 30's Gibson in now to show you what I would consider "normal". That kerfing is loose at it's bottom corner in all sorts of spots, simply because it was never clamped down tight to the rims at the factory. Still holding fine though, and is nothing that I would go after.

BTW - all the squeeze out, pieced together kerfing, pencil lines and tooling marks - I mean, like, OMG!! How could any guitarist with an ounce of self respect be caught dead with one of these things! They must be worthless. I'm sooo glad that our trade has progressed to value what's really important.

(Yes, I'm making fun of nearly everyone here....)

_________________
Eschew obfuscation, espouse elucidation.

Well, I went back tonight and checked this very carefully from inside and out. This revealed that my earlier diagnosis was a wrong headed assumption. Big surprise, right?

I just bought this guitar recently. I'm fine with it being banged up, but what started me snooping around was an odd noise that I happened to notice while playing it the other night. There is indeed evidence of past damage in the suspect area. If I push against the top where it meets the side (near the scarred area below) I can hear a kind of click, like something is loose, but the top doesn't move or flex.



After this closer inspection, it appears that what I mistook as movement in the lining was actually just my piece of dowel knocking loose some of the dried squeeze out of that weird, bubbly glue that David described earlier. (I've stopped prodding it.) It may be that someone else has tried to remedy this clicking noise in the past. In the pic below it looks like there is some other kind of glue in the shadowy section where the top meets the lining. However, I could be totally wrong.



I'm not sure what's going on here. I'll keep an eye on it and see if anything changes. Meanwhile, I'll just play the heck out of it.

Thanks for all the replies. I appreciate your willingness to share a bit of your experience and expertise.

George

_________________
George :-)

This makes more sense now. Possibly the top is loose from the linings where it got hit. Does the binding move, or the top move relative to the binding when it "clicks"?

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard,
As far as I can tell nothing is moving--not the top, the side, or the binding. However, in addition to the clicking noise I can hear a different tone--kind of a dead sound--when I tap against the binding in the area. Perhaps the binding has lost it's adhesion in that spot? Maybe a touch of thin CA glue? Unless there is something else to be done to diagnose this issue, my thought is to do nothing, observe things for a while and see if anything changes.
Thanks for your reply,
George

_________________
George :-)

David, thanks for the info on the weird glues Gibson used. That's good to know about. BTW, what's "RF-cured"?

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Radio Frequency cured - microwaved, basically. I'm not 100% sure however, as though I've heard it referred to as such many times, I've never actually sourced or referenced that information. I don't know what actual adhesive base it is - almost looks like a slightly foamy resorcinol. I stopped by Eldon's today and was hoping to talk to him about it, but he was away. I'll try to see later this week if he knows what it actually is, as I'd be curious to know what it really was as well.

_________________
Eschew obfuscation, espouse elucidation.

Thanks, David. Radio Frequency was my guess, actually, but I wasn't sure. I'd be very interested to learn of anything more you find out about this, if you're willing to pass on the info.

Thanks again!

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/