Gibson A mandolin (1916) - brace repair, bridge and general advice needed

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Gibson A mandolin (1916) - brace repair, bridge and general advice needed

Postby John Scime » Fri Mar 09, 2012 11:53 pm

I recently bought this old Gibson A - 1916 (I'm told) with ser #27265 . It is in generally good condition other than the brace needing glue on the treble side. My goal is to make it playable for my own use.

I've glued lots of braces before, but this one really doesn't "yield" or close to the top easily. I'm afraid it might break free in the process making the repair more difficult for this moderately experienced novice. I would appreciate any guidance on this job. I have at my disposal many clamps, hide glue, and even a stew-mac scissor-jack-clamp (not sure if it will fit). I would appreciate any guidance on this job.

The bridge on the right is what came with it - obviously not original, but is it possible to tell if it is a Gibson replacement? The bridge on the left is from a 1935 Kalamazoo flat-top oval, made by Gibson. It is shaved really low - but I am wondering if any experts out there can tell whether it is the same template as a pre-loar era Gibson one piece bridge. If so I may use it as a template. Otherwise the adjustable's pins are wobbly - can I simply glue them in straight and will this approach last?

Lastly, the pick-guard brace is celuloid or mock tortoise shell and missing both the half-circle clamp block and the old clamp. I would like to fashion a replacement clamp using a modified violin chin rest. Can anyone point me to a drawing or photos of an original unit to assist in making the parts I require (other than the clamp that is)?

Thank you in advance.

John
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John Scime
 
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Re: Gibson A mandolin (1916) - brace repair, bridge and general advice needed

Postby John Hamlett » Sat Mar 10, 2012 11:36 am

When those braces are loose for a period of time, the string pressure on the bridge makes the top sink. You'll need to restore the arch of the top before re-gluing the brace. Sometimes, just removing the strings for long enough will allow the top come back into shape, otherwise, you can probably do that by putting some kind of jack inside the mandolin and gradually (over a period of days or weeks) keep tightening the jack until the arch is restored. Heat may be needed to restore the arch if it's a more severe case.

Neither bridge is original, and neither looks like the original did. You'll need a replica bridge, or a new adjustable bridge, better than the one in the picture. I might suggest stopping in over at mandolincafe.com. If you haven't been there before, you may feel kind of lost for a while, but you eventually can find pictures of bridges, pick guard clamps, and plenty of knowledge about these old Gibsons. Take care of that pick guard, by the way. Those things can be worth hundreds of dollars to people who want to restore old Gibsons.
John Hamlett
 
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Re: Gibson A mandolin (1916) - brace repair, bridge and general advice needed

Postby John Scime » Sat Mar 10, 2012 1:33 pm

Thanks, John, for your help. What you say makes perfect sense and that is what I will do.

On the subject of the pickguard, btw, can someone describe how I might remove this (attached by two pins into fretboard) while I do this work?

Thank you!
John Scime
 
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Joined: Thu Mar 01, 2012 5:04 pm
Location: Mississippi Mills, Ontario

Re: Gibson A mandolin (1916) - brace repair, bridge and general advice needed

Postby John Hamlett » Sat Mar 10, 2012 1:43 pm

Those things have two standard, hardware store steel brads holding them on, usually, and they usually rust and virtually bond themselves in place.
The standard, but certainly not recommended method, seems to be to jam a screwdriver between the pick guard and the fingerboard, give it a twist, move up and down the "crack" and repeat so that there is damage to as much of the pick guard as possible, judging by many of the ones I see.
A better. and perhaps more highly recommended method, is to -carefully- lever the guard by grasping the bridge end and pulling out in the direction of the edge of the instrument. Hopefully, a little movement will show up at the fingerboard edge. A shim can then be inserted (plastic picks, pre-approved credit cards, old hotel door keys are all good candidates). By alternately rocking the guard back and forth and and inserting more or thicker shims at both ends of the 'crack', usually the brads will pull out on one end or the other. You may find them to be bent at an angle and the direction the guard will need to move, in that case, is up as well as sideways until the guard is free. Take you time, sometimes that old celluloid is fragile.
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Re: Gibson A mandolin (1916) - brace repair, bridge and general advice needed

Postby Michael Lewis » Sun Mar 11, 2012 2:59 am

A very good replacement bridge for those one piece bridges is a BREKKE bridge from the Weber folks at STE. They are roughly the same size and shape as the original and the best part is they are adjustable and not very expensive. You will have to fit the bottom of the bridge to the top of the instrument.
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