Bowlback repair

[JeffD]

I am considering resurrecting an old (1917?) Martin bowlback. The most egregious problem is that the neck has separated from the body, (you can slip a piece of paper in the gap).

I have heard that this is the death knell for bowl backs, so I haven't really pursued it. Do you think this can be fixed?

The mandolin could use a little fret work too. It would be a fun instrument to play if restored properly. Right now its a wall hanger.

[Paul Hostetter]

It can be fixed. From simply gluing it back to reinforcing the joint after pulling the board, you have options. The time involved might not be justified on a lesser instrument as an identical whole instrument would cost less than the repair, but a Martin is another story.

[brunello97]

Jeff,

Many, if not most US made bowlbacks had a neck/neckblock joint of some kind-I've mostly seen dovetails, but there probably are others. Many if not most Italian made bowlbacks have the neckblock integrally carved as part of the neck-though there may be other versions. #With this design, if the neck moves, rotates, breaks etc. etc. at this junction the repair consequences are more complicated-this may be the source of the 'deathknell' rumors you've heard.

As Paul indicates, removing the fretboard will reveal the joint-on most US bowlbacks, including Martin. # Is the joint loose? #Might you be able to steam apart the neck/neck block joint, clean it up and reglue it? #(It is tricky but easier than it might sound.) #I've done it on a number of old L+H and Washburn models to get my chops down. With some of the thicker fingerboards the whole deal is a slice of pie. Cosmetic precautions and touch up can outweigh the structural rigamarole.

Post some pictures if you can, there are enough folks around here to talk you through it. Maybe even Tappet Bros. it a bit. I agree, a Martin bowlback is quite worth the effort. I've got a modest 1907 bb that sounds and plays great. I have to keep myself from licking the rosewood. #Needed a bit of chiropractory of its own, btw.

good luck,

Mick

[dave17120]

Hi Feff,
"I am considering resurrecting........"

Does this mean perhaps you are thinking of doing it yourself?

The main reason, from what I understand, that problems like this "spell the death knell", is not that it CAN'T be fixed, but that it would cost a great deal to get a luthier to do it... if, as Paul says, it is a "lesser instrument".

It can be complicated and time consuming, but do-able.

Any photos? regards, Dave

[JeffD]

Does this mean perhaps you are thinking of doing it yourself?



Any photos?


I will put up some photos later this week. Its a Martin, and best I can tell from pictures in an old Martin picture book it was made somewhere around 1917.

It had a sweet tone - not an impressive amount of volume, but very sweet overall - and I would love to get it playable again.


No I would not attempt it myself. You don't want me anywhere near hand tools.

[MandoSquirrel]

Eugene may know something about the construction details; he's the authority on Martin Bowlbacks around here.

[John Zimm]

On this note, I recently bought two old bowlbacks in need of a lot of repairs that I plan to do myself to learn a thing or two about lutherie. #On one of them the bottom part of the neck is separated very slightly from the body-a piece of paper can fit in the space but not much more than that. #I took off the fingerboard and to my eye the neck joint looks perfectly stable. #It is a dovetail joint and the neckblock and neck are very tight against each other. #So, my question is, is the gap acceptable if the neck appears stable, or should the neck be removed and fit more perfectly? #

-John.

[dave17120]

"my question is, is the gap acceptable if the neck appears stable, or should the neck be removed and fit more perfectly?"

The question really should be was the neck straight? If its stable, its a lot easier NOT to mess about with it, but if the neck is bowed, usually somewhere around the 10-12 fret, then something needs to be done.
Also, is there any sinking of the top?
Tricky to check now with the f/b off but, lay a steel rule along the top with the f/b taped back on, and see if you have enough height for a bridge, and still have a decent action. And is the f/b flat?
If it has a bend, there are less drastic alternatives than removing a stable neck from a bowl.

[Paul Hostetter]

If the neck is separating from the body, which is typical and understandable, and the action's sky-high, it hardly matters if the neck is straight. You don't judge the condition of the neck joint by looking at it from the top with the board off, you look to see if the heel's coming up, which is evidently the case here.

A "little gap" translates to a major difference in action, and is a clear index of whether the neck joint is OK or not. And neck joints on bowlbacks don't bow around the 10th-12th, the 10th is at the body join where nothing "bows" anyway.

First things first. Get the neck thoroughly attached at the right angle, then put the board on and true it.

[John Zimm]

"my question is, is the gap acceptable if the neck appears stable, or should the neck be removed and fit more perfectly?"

The question really should be was the neck straight? If its stable, its a lot easier NOT to mess about with it, but if the neck is bowed, usually somewhere around the 10-12 fret, then something needs to be done.
Also, is there any sinking of the top?
Tricky to check now with the f/b off but, lay a steel rule along the top with the f/b taped back on, and see if you have enough height for a bridge, and still have a decent action. And is the f/b flat?
If it has a bend, there are less drastic alternatives than removing a stable neck from a bowl.

The top was off when I bought it. #I'm not sure what happened, but the top was cleanly separated around the rim and then snapped off at the neck. #

I'll check it tonight and see about the straightness of the neck. Theoretically speaking, say there is a bow in the neck, what would a guy do to straighten it?

Thanks for all the help.

-John.

[dave17120]

As everything is apparently already nicely disassembled, then you may as well try and take the neck out. A photo of the join would be good.
Use steam to loosen the glue.... Stew Mac does a faily cheap steam needle. The neck should come out easily. Hahaha??!! They always make it sound so easy..... it rarely is, but you are 3/4 of the way there.
The real tricky bit then is to adjust the neck/heel block join to change the angle of the neck. Usually when they say, 'there is a bend in the neck', its actually at the join, around fret 10, not in the neck at all. If your neck is actually bent, your solution depends on how much.
Again, a photo would be good.
Keep us posted, Dave

[Jim Garber]

My style 6 Martin had a bowed neck and Jim DeCava fixed it by judicious humidifying and great patience. The neck join was not loose on this one tho. Dave is correct about seeing whether it is the neck join vs. a real warp (or both). Everything is fixable-- depends on skill and patience. There is no such thing as a dead mandolin!!!

Jim

[JeffD]

Any photos? regards, Dave

A few pics to show the mandolin condition in general

[JeffD]

and another

[JeffD]

and yet another

[JeffD]

the neck is straight

[JeffD]

Alas, here is the problem.

So folks, what do you think. Is this mandolin:

1 - repairable?

2 - worth the cost of the repair?

[dave17120]

"And neck joints on bowlbacks don't bow around the 10th-12th, the 10th is at the body join where nothing "bows" anyway."

I do know that..... perhaps I should more acurately have said fingerboard. If you get a dip, its usually around frets 10-12, and is often described as 'the neck is bent'. It is usually the heel that moves, sometimes bursting the back of the bowl. Apologies for the inaccurate use of terminology.

Your photos seem to show a mandolin in not too bad shape. BUT.... how deep is the separation? Is there ANY movement??? and with a decent action, do you have enough room for a bridge?

If you have room, and the crack is not too deep and its stable, I'd be inclined to put light strings on it and enjoy playing it.
Dave

[JeffD]

Your photos seem to show a mandolin in not too bad shape. BUT.... how deep is the separation? Is there ANY movement???

Yes there is movement - and the separation increases I bring the strings up to tension. You can use the neck movement like a whammy bar on a stratocaster, if you are a mando-sadist.

A friend told me to take off the strings, and just squirt some glue in the gap, and clamp the gap shut for 24 hours.

My response is that I don't squirt no glue into nothing, I call the luthier.

[dave17120]

Ahhhh.....
if you have movement, then some thing needs to be done. As mentioned previously, they say problems like this signal the death knell of a bowlback, mainly because of the cost of the work to put it right. To get at the neck/heel assembly, you are likely to need the f/b and the top off. If you are lucky, (and many American instruments seem to be done this way from what I can tell) the neck will be fitted into a dovetail joint. If you are unlucky, the whole heel is carved as one, and the bowl glued to it. Most likely the former, if you have movement, but no splitting in the top of the bowl.

You have to decide how much its worth to you I guess. Dave

[brunello97]

Jeff, Most likely you will not need to take the top off to get to the neck joint on your Martin. In the L+H and Martin bowls I've had apart, the top does not cover the neck/neck block joint (as it does in the Italian bowls I've operated on.) Taking off the fingerboard should give you access to the joint. I did the do on my Martin 00 and the dovetail was right there. Fingerboard removal has been discussed here often and a search should turn up useful instruction. Take it slow and careful and you should have no problems.
Mick

[oggiesnr]

25 years ago a cheaper bowlback of mine had a similar problem. Not knowing a luthier I took it to a friend who made electric guitars. His solution was to clean the glue from the joint, re-glue it and hold it in place with strong elastic bands until it set. result was a playable instrument which I played for another ten years and then sold on locally, last I saw it was still going strong!

Now it wasn't a Martin and it's probably (certainly) the wrong thing to do, but if the alternative is junking the instrument I offer it as a last resort.

Now ducking for cover

Steve

[Jim Garber]

Now ducking for cover

No ducking necessary here. I think quite a few of us would welcome the cheap and dirty methods esp for all those instruments that would not require the "correct" lutherie method.

Jim

[brunello97]

..... and hold it in place with strong elastic bands until it set.

Now ducking for cover

Steve

Providing, of course, that only the PROPER rubber bands were used in the operation.

With a sincere nod and wink to all the true luthiers who have generously supplied their knowledge, experience, wit and patience to all of us (me particularly) in the course of many enjoyable conversations....

Mick

[Michael Lewis]

I wouldn't recommend just gluing it and hoping for the best. That method may work but it may not. The problem arises if it doesn't work. At that point you have a bigger mess to deal with.

The problem probably stems from the fact that wood dries out and shrinks. In this case the joint should be steamed apart and cleaned. When all is dry shims can be added and the joint refitted properly. Might be good for another 90 years.