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Repairing a old Gibson archtop

If you have a string instrument of any kind that needs fixing, a mistake you made in building a new instrument that you need to "disappear," or a question about the ethics of altering an older instrument, ask here. Please note that it will be much easier for us to help you decide on the best repair method if you post some pictures of the problem.

Repairing a old Gibson archtop

Postby Steve Graves » Sun Dec 02, 2012 2:42 am

The top of my 1921 Gibson L2 has a split along the bass bar. This guitar only has two small f holes for access to the inside. Simple gluing does not work and will re-open. I normally put a cross grain spline but the bass bar gets in the way and is carved from the top. This guitar is in all original shape and looks just like the guitar Robert Johnson borrowed from his friend for the only photo we have of him so I do not want to take the top off. My repairman in New York City is very old now. Chico traded me this guitar and said he took it in back in the 40s for some money he was owed for strings and such. Chico works above Sam Ashes' original store. What is a poor boy to do ?
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Re: Repairing a old Gibson archtop

Postby Michael Lewis » Mon Dec 03, 2012 1:25 am

You could hang it on the wall, sell it to someone else, or take the back off. The latter is not to be undertaken lightly. If you remove the back you may (probably) have to replace much if not all of the lining material, and also probably have some finish "touch up" to do. It takes some skill to get things apart and back together and still look right.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Fri Dec 07, 2012 7:10 pm

Just today i have been given a link to an impressive thread in a different forum demanstrating such a repair in detail: http://www.euroguitars.co.uk/viewtopic. ... 19107ba486
Please note that i am not a member of that forum!

I am just having a similar problem concerning an old Isana archtop where the bars had been cut in order to mount PAFs. It needs to be opened from the bottom for repair:

Image

The guitar has been hanging on the wall for meanwhile over 25 years because i do not know how to open it without destroying the lower binding which seems to be higher than the thickness of the (laminated) bottom.
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Re: Repairing a old Gibson archtop

Postby Michael Lewis » Sat Dec 08, 2012 1:52 am

You might destroy the original binding but it can be replaced. If the binding covers more than just the edge of the top plate (cut into the side material) then the binding must be removed to gain access to the seam between the plate and the side. The finish should be scored with a sharp knife all along the binding so chipping of the finish is kept to a minimum. A thin knife or spatula is inserted between the side and the plate being very careful to avoid damage of either part. The blade is worked around the edge from block to block, then the other side is done the same. Lastly the blocks are freed from the plate. all this working with laminated plates will be a stressful operation to avoid damaging the parts.

Hot water to heat the blades and wet the glue is usually helpful, but finding out what type of glue is holding the parts will let you know what sort of 'solvent' to use. Water and heat helps with hide glue and polyvinyl/aliphatic resin glues, but if it is assembled with a waterproof glue such as resourcinol only physical separation will open the seam.

The job can easily become very involved requiring finish work. Hopefully it will go well and fit together again nicely and without much touch up work.
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Re: Repairing a old Gibson archtop

Postby Bob Francis » Sat Dec 08, 2012 1:37 pm

Nothing to ad but a thanks to Beate for the interesting article.
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Re: Repairing a old Gibson archtop

Postby Steve Graves » Sun Dec 09, 2012 12:42 am

So no one has any experience with the violin family and such repairs? Will cleats work and are they possible without taking the guitar apart?
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Re: Repairing a old Gibson archtop

Postby Michael Lewis » Sun Dec 09, 2012 3:03 am

In the violin world either the top or back gets removed to make repairs on the inside, but violins are designed for such work. In general, guitars are not made to be taken apart, therefore it is often rather difficult and puts the instrument in jeopardy to do such operations, which is why it takes skill and experience to do it well.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Sun Dec 09, 2012 2:27 pm

Thats right. Good example is the old archtop i showed above. Binding higher than top or bottom and more or less no tolerances putting things back together. To my understandig, building a mould for the body and leaving it in it while the body is open is almost a must in such jobs.

BTW. i think i will cleanly start a new project and ask some questions on possibilities to work from outside and through the holes (which AFAIK is done with guitars wherever possible). With some up to date and detailed pictures, if You don't mind.
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Re: Repairing a old Gibson archtop

Postby Mark Wybierala » Sun Dec 09, 2012 6:54 pm

Yup violins pop apart quite nicely compared to the complexities and uncooperativeness of most guitars. This is a job for someone who has done this more than a couple times. I've gone there and won't go back. I commited a sin against what could have been a rather nice Orphium tenor archtop. The guitar gods slapped me back to my place in the luthery food chain. I can keep my self respect by sticking to fretwork. "Level" is a concept that I can understand.
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Re: Repairing a old Gibson archtop

Postby Steve Graves » Tue Dec 11, 2012 12:59 am

Do some of the older arch tops come without binding ? Put together similar to a violin where the top and backs are simply larger than the side profiles which would not need binding and be easier to repair this building style must have been considered.
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Re: Repairing a old Gibson archtop

Postby Barry Daniels » Tue Dec 11, 2012 11:14 am

Steve Graves wrote:Do some of the older arch tops come without binding ? Put together similar to a violin where the top and backs are simply larger than the side profiles which would not need binding and be easier to repair this building style must have been considered.


No. Never seen it done.
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Re: Repairing a old Gibson archtop

Postby Dave Stewart » Tue Dec 11, 2012 11:40 am

Never seen older ones, although I've done a few.
Attachments
901 detail back on black 92.jpg
803 soundholes 89.jpg
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Re: Repairing a old Gibson archtop

Postby Michael Lewis » Wed Dec 12, 2012 2:40 am

I have seen one archtop guitar with cornice work on the outside like on a upright bass rather than on the inside like a violin. None of the factories I know of did this.

It is accepted procedure to remove the binding and separate the seam. Often many old instruments are starting to open themselves in places. The difficult areas are separating the plates from the blocks.

Beate, possibly you could put in some "sound posts" under the cut ends of the braces through the sound holes to keep the top from collapsing, and avoid removing the back. Being the guitar is electric it doesn't need good acoustic resonance. It might work.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Wed Dec 12, 2012 5:10 am

First a question to the board stuff: the part on my Isana takes so much place that it might be helpful to split it off into its own thread, won't it?


A year ago i filled the gap between the pickup hole and the neck block with wood working through the holes - You might see it in the photos. I tried to fit the wood to the curvature of top and bottom. Not very easy, especially because the top seems to be slightly sunken in near the neck joint. The additional block is glued to the bottom, and it should be possible to destroy it when the back is opened.
I tried to glue small bars of spruce outside the pickup holes. Everything very raw. It was more or less the last of several failed attempts trying to fix the body without opening it. Nicety was not a concern.

It looked as if the operation failed again.

The guitar hang on the wall under permanent but reduced string tension. After correctly adjusting the bridge and tuning the guitar it looks as if everything might have settled, especially the weak neck joint. Only at first sight, of course; i would like to observe that over the next weeks. If that really turns out to be true, the weakest point will be the missing trussrod.

But now it is time to at least plan the remaining recovery.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Thu Dec 13, 2012 6:17 pm

Mark Wybierala wrote:...This is a job for someone who has done this more than a couple times. ... "Level" is a concept that I can understand.


Indeed. But even an exprienced Luther would have no chance against some of the old sins (irregular holes in the top...) Furthermore, at the time i tried the first repairs such guitars were more or less worthless.

Here are some pictures. I know, quite shocking:

First, the previous owner converted the headstock. I had to shorten it in order to be able to fit the guitar into its case without applying massive additional tension on the neck. It had already warped, and i had to bend it back again.

Head.jpg




Next problem area: pickup hole and cut bass bars. I tried to stabilize that by roughly fitting wooden blocks working through the holes and by temptatively adding small bars outside the pickup hole. In the place of the large circular hole there was a large irregularly shaped hole made by the previous owner. I extended it to the smallest possible circle and fitted the maple inserts into it as a means of "least possible evil".

PU1.jpg
PU1.jpg (19.28 KiB) Viewed 7864 times


Hole_2.jpg


Sustainblock.jpg


If the body was opened, i would remove all this crappy stuff. But i would keep it if it was successful. Never change a winning team.
Last edited by Beate Ritzert on Thu Dec 13, 2012 6:30 pm, edited 1 time in total.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Thu Dec 13, 2012 6:27 pm

Further problem area: neck joint.

The original neck joint was loose. I decided to insert e block of spruce and to cut a new joint. A mistake i would avoid from then on; the neck joint turns out to be still very weak. But i would like to avoid to touch it if ever possible.

Neckjoint_1.jpg


Neckjoint_2.jpg


Last (?) problem area and on the long term possibly the largest: the neck itself.

Neck_Curvature.jpg


This neck consists of 3 stripes of would, probably maple, beech, or birch. Hard so see through the finish. Apparently it has been built without a trussrod - the cover is a fake. So it is probably subject to bend a 2nd time under string tension.
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Re: Repairing a old Gibson archtop

Postby Mark Swanson » Thu Dec 13, 2012 6:34 pm

Hmmm...if it were me, I'd dismantle the neck joint. Then stabilize and do any repairs to the neck block and the guitar body, and then make sure the neck can be put back on and be tight and strong. I have come to realize that a sloppy or weak neck joint can really pull a lot of tone away from a guitar that otherwise would sound good.
With the neck off, it may well be easier to repair the body too.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Thu Dec 13, 2012 6:47 pm

Mark, my main concern is that i actually weakened the neck foot itself by cutting a dovetail joint into that fairly small foot. That was the mistake i would try to avoid; and even after 25 years i am still frustrated having done that. If it was not visible from the outside i evend would consider using a screw (and if the body was thicker i would have added one and hid it in the strap pin).


Some questions - again at present the acustic sound is really nice, better than many laminated thinlines. So i would like to restrict my efforts to the absolute minimum.

  • is it possible that this sustain block and especially these small bars are enough to stabilize the body? Without these bars, the top continued to sink in under the tension of even light strings. I am uncertain if this will be enough on the long term.
  • how can i judge if the neck joint is now stable or not? Now, one year after my last changes (shown here) it is at least way better than it ever was since i own the instrument. Is it possible that the fingerboard i in sufficiently close contact to the top and hence the underlying block that it will remain stable?
  • should i consider removing the fingerboard and implementing a trussrod, maybe as an insert of machiche wood (which is a lot stronger than the wood the neck is made of) or aluminum? Or do You think the neck is just ok and i should better leave it as it is?
  • what about the finish? Last night i covered the open cuts into the laminated woods and the breakouts with nail polish. I happen to own suitable colors. How would You repair the finish? Would lightly sanding the area around the large hole with grain 1200 wet and then carefully polishing the laquer be sufficient? I am interested in just retaining the look of this 40 year old but otherwise fairly good finish and to keep the character of the guitar.
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Re: Repairing a old Gibson archtop

Postby Beate Ritzert » Thu Dec 13, 2012 7:21 pm

Final topic: optical restauration. The intention of this post is just some brainstorming on the possibilities.

I am considering to recover at least the head, if not possible, then "closely". I further need to replace two of the neck inlays, which have overheated while i was straightening the neck.

Here some Isanas in black rose finish:

http://www.musikkeller.com/mk/_bilderverwaltung/images/mk/semi/2120080mk.jpg
http://www.musikkeller.com/mk/_bilderverwaltung/images/mk/archtop/2090230mk.jpg

The specialty of my guitar are the blonde sides. That's why i decided to fill the holes with maple and supply the guitar with maple hardware. Just try to give it a new identity of its own if the one orininally intended was not attainable any more.

How would You handle the holes? Would You leave them in maple? If not, what else?
Last edited by Greg Robinson on Sun Dec 16, 2012 11:56 pm, edited 1 time in total.
Reason: Converting inline images to links.
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Re: Repairing a old Gibson archtop

Postby Michael Lewis » Fri Dec 14, 2012 2:41 am

If the guitar is to be played I think the neck should have an adjustable truss rod installed, and the neck to body joint re-worked. My perspective is "if it can't be played then why bother with any of the other repairs"? Each repair is just another step along the journey, and eventually the guitar will be playing again in good form.

If the back is removed then the neck block can be replaced with a more robust structure. The neck joint could be redesigned to be stronger and more stable.
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