Don't do this!

[sunburst]

I've had this older Kentucky KM 1500 in the shop for a long time, waiting for me to get around to fixing it. The neck had come loose and it's position was shifted so that the mandolin was basically unplayable. It was the owners first good mandolin, so he wanted to spend the money to get it playable again by having me re-set the neck.
Today, I finally got it out of the case and started taking it apart, expecting an easy time of it, using heat and steam to soften the AR glue that I figured it was assembled with when it was made.
I worked myself into a sweat getting the fingerboard off, heating the fingerboard and forcing a putty knife into the joint. The glue was stiff, gummy feeling and so hard to release that I split some of the ebony loose from the underside of the 'board, but I finally got it off. The glue was yellow colored, like Titebond, but Titebond releases much more easily with heat. Hard to figure, but I continued. I managed to get the extender piece separated from the top with only a little spruce split off of the top and there were two kinds of glue under it. Some white stuff with the yellow stuff over it.... and some foam! (Hmmm...)
Onward to steaming the dovetail and removing the neck. The neck was already coming loose, so it didn't take long with the steam to get the neck wobbling around, loose in every direction, but still not coming free of the body. I probed with palette knives and other tools and finally got the neck out of the body. I don't know if I did it, using as much force as it took to get the neck loose, or if the crack was already there, but now I have to remove all this gummy junk and repair the head block before re-setting the neck.

I've never used it before, so I don't recognize it from experience, but I assume this is Gorilla glue. Whatever it is, don't use this stuff to "fix" instruments! Not only did it not hold, but it has made my job much more difficult trying to actually fix this thing!
If you're reading this and recognize it as something you did, now would not be a good time to tell me about it. I already feel like I've got more work in this thing than it is worth, but hopefully the worst or it is behind me now.

[MikeEdgerton]

The give away is the foam. It's Gorilla glue. I've used it on some badly damaged wood furniture that wasn't very valuable. You wet the surfaces to prepare them and it foams. I'm honestly surprised you didn't do more damage getting it apart.

[sunburst]

I'm honestly surprised you didn't do more damage getting it apart.

Thank you for that vote of confidence!

[MikeEdgerton]

This stuff is tough. I had a few chairs that belonged to my wife's family that looked like they had been through bar room brawls. Gluing them with Titebond didn't hold. Gorilla glue has. I don't intend on taking them apart ever.

[sunburst]

While we're on the subject of mandolins of moderate value that need extra work because of someone's misguided repair attempts, here's what I found inside this old Army Navy mandolin. It's taken me the last couple of days to clean all this glue out if the inside of the poor mandolin. (Not working steadily on it of coarse, but dissolving sections at a time.) I simply don't understand why someone thought slathering all the glue around in there was a good idea, but at least this is not Gorilla glue!

[amowry]

Eesh!

[DavidKOS]

The give away is the foam. It's Gorilla glue. I've used it on some badly damaged wood furniture that wasn't very valuable. You wet the surfaces to prepare them and it foams. I'm honestly surprised you didn't do more damage getting it apart.

This stuff is tough. I had a few chairs that belonged to my wife's family that looked like they had been through bar room brawls. Gluing them with Titebond didn't hold. Gorilla glue has. I don't intend on taking them apart ever.

For that sort of repair Gorilla glue is pretty useful, but it sure foams up like an SOB. I rarely use it unless absolutely needed.

I can see how that would be terrible stuff to deal with on a musical instrument.

[multidon]

John, when I was teaching orchestra I learned to do some of my own repairs. I of course had a luthier I took jobs to that I could not handle. On of my kids dropped a rather inexpensive school owned cello and the peg head broke clean through the peg box and bisected the peg holes. I knew I was out of my league so off to the luthier I go. I was told the damage was terminal and there was no hope. Then the luthier told me there was one thing I could try. Gorilla Glue. The luthier wouldn't do it but I was told I should go ahead and try it as there was nothing to lose. I wet the surfaces, applied the glue, and lined everything up. It was a clean break. I clamped it by hand and scraped off the foam as it appeared before it had a chance to harden. Used a reamer to clean out the holes, refit the pegs, and we were back in business.

There were light collored jagged repair lines I didn't bother trying to touch up. I don't even know if you can touch the stuff up. Kids liked it though. They named it "Frankencello".

So here is a case where it worked when nothing else would have. But cases where it would be the right choice are rare I'm sure.

I really think that's what you have on the Kentucky. And you are going to have to scrape it all off. I don't know of any solvent that works.

[Pete Jenner]

Great photos.

[Gail Hester]

Bravo for getting that one apart John.

On the subject of bad repairs, some of you may remember this 1927 Gibson F2 that I posted pictures of years ago. Don't do this either.

[Steve Sorensen]

[Tavy]

Nice shots of the Gorilla there!

Here's a couple of my favorites, first off a collapsed Gibson A3, previous repair had done nothing at all to stablise the poor thing:



Then I never get tied of showing this one:



It had (thankfully long dead) woodworm too!

[John Arnold]

Fortunately, I have not encountered this on a reset. However, I have removed a few bridges that had been reglued with Gorilla or a similar polyurethane glue.

[Bernie Daniel]

John, when I was teaching orchestra I learned to do some of my own repairs. I of course had a luthier I took jobs to that I could not handle. On of my kids dropped a rather inexpensive school owned cello and the peg head broke clean through the peg box and bisected the peg holes. I knew I was out of my league so off to the luthier I go. I was told the damage was terminal and there was no hope. Then the luthier told me there was one thing I could try. Gorilla Glue. The luthier wouldn't do it but I was told I should go ahead and try it as there was nothing to lose. I wet the surfaces, applied the glue, and lined everything up. It was a clean break. I clamped it by hand and scraped off the foam as it appeared before it had a chance to harden. Used a reamer to clean out the holes, refit the pegs, and we were back in business.

There were light collored jagged repair lines I didn't bother trying to touch up. I don't even know if you can touch the stuff up. Kids liked it though. They named it "Frankencello".

So here is a case where it worked when nothing else would have. But cases where it would be the right choice are rare I'm sure.

I really think that's what you have on the Kentucky. And you are going to have to scrape it all off. I don't know of any solvent that works.

Interesting that the luthier believed that Gorilla glue was the last hope. I am pretty sure that in one of the glue tests that I have seen (might have been Popular Mechanics or the like) Gorilla glue was NOT as strong for wood joints as some of the more conventional glues like Titebond or hide glue. This was a scientifically controlled test with standardized joints and a device to record the break pressures required. The polyurethane glue failed at lesser pressures.

[Jim Adwell]

While we're on the subject of mandolins of moderate value that need extra work because of someone's misguided repair attempts, here's what I found inside this old Army Navy mandolin. It's taken me the last couple of days to clean all this glue out if the inside of the poor mandolin. (Not working steadily on it of coarse, but dissolving sections at a time.) I simply don't understand why someone thought slathering all the glue around in there was a good idea, but at least this is not Gorilla glue!

John, I was talking to a guy the other day who made violins, or so he said, and he mentioned that one could "stiffen the top" by brushing hot hide glue on the inside, with a "stiffener" in the glue. When I asked what the stiffener ingredient was, he said that various things worked, but the low-tech item, if you will, was garlic. Perhaps your mandolin is the result of someone trying this. In your pictures it looks more like yellow PVA glue, though.

[jim simpson]

It's too bad whoever did the previous repair didn't take time to make sure the joint was a good enough fit before gluing. I was first afraid to hear that the glue was from the factory. On this level of instrument, that would be shocking. I guess the worst part of this repair is undoing the previous efforts (bad glue, etc.)
I'm sure your outcome will be good.

[Nevin]

I spent more hours than I like to think cleanin gorrilla glue from a broken bass scroll. The stuff is a menace. Oh and no the old repair had not held.

[juneman]

I ran into this on an old 000 martin repair. fiberglass cloth and a pick!

walter johnson

[DavidKOS]

Then the luthier told me there was one thing I could try. Gorilla Glue.
.....scraped off the foam as it appeared before it had a chance to harden. Used a reamer to clean out the holes, refit the pegs, and we were back in business.
....
So here is a case where it worked when nothing else would have. .

Well done - although a more expensive cello would have warranted a peghead splice, to replace the broken one.

[MikeEdgerton]

Bravo for getting that one apart John.

On the subject of bad repairs, some of you may remember this 1927 Gibson F2 that I posted pictures of years ago. Don't do this either.

Nice.

[High Lonesome Valley]

John, I was talking to a guy the other day who made violins, or so he said, and he mentioned that one could "stiffen the top" by brushing hot hide glue on the inside, with a "stiffener" in the glue. When I asked what the stiffener ingredient was, he said that various things worked, but the low-tech item, if you will, was garlic.

Obviously a Transylvanian repair technique

[Denny Gies]

John, thanks for the story. I can't imagine doing the kind of work you do.....really appreciate it. By the way, the dawgs are doing fantastic here in Gainesville.

[oldwave maker]

John- it weren't me, cuz I always use fresh hoof glue with rusty horseshoe nails on the neck joint repairs, leaving 1 sticking out a bit for the strap hanger. You dont want to coat the insides with fresh garlic, the moisture will cause problems. Wait till its been out of the ground several months........

[MikeEdgerton]

John- it weren't me, cuz I always use fresh hoof glue with rusty horseshoe nails on the neck joint repairs, leaving 1 sticking out a bit for the strap hanger. You dont want to coat the insides with fresh garlic, the moisture will cause problems. Wait till its been out of the ground several months........

Was either done by a luthier or a farrier. I like it. I like it a lot.

[sunburst]

I suppose misery loves company... Thanks for the pics and stories. It's good to be reminded that other people have to clean up after the kind of... umm... "repairmen" that cause these situations.
Bill, can you send me some of those rusty horseshoe nails? All I can find are still bright and shiny. I suppose I could leave some of them out in the weather for a while to rust.


As I was cleaning the foamy, gummy, junk off of the neck heel, this showed up. A little piece of maple, Gorilla butt-jointed onto the end of the dovetail tenon. Some serious structural strength there!
After removing the foamed on piece of maple, the dovetail tenon is less than 3/8" long and about 1/4" wide. I was debating how to reattach this neck, and starting to consider bolts or some other hardware, and now that you mention it, I think I can clinch a couple of horseshoe nails at the inside of the head block by using a long punch through the end pin hole!