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Thread: 1948 Martin 2-15 Repair Questions

  1. #1

    Question 1948 Martin 2-15 Repair Questions

    Hello all!
    I recently came into possession of 2, 1948 Martin&CO
    2-15 mandolins. But they both have issues that need fixing so I thought I'd check here to see if anyone has some information for me. I'll post photos below as well. Basically each one has issues the other doesnt so I'm planning on swapping out parts to get one put together nicely.
    For reference with the photos I am calling the mandolin I am planning on restoring number 1 or 1st, and the other number 2 or 2nd.
    The one im planning on restoring, 1, is in relatively good shape except there's a piece of the f-hole knocked out on the soundboard. It also has an after market pick guard, replaced tuning gears and is missing it's tailpeice, but the other, 2nd, mandolin has all of those original parts that can be transferred. Also, on 1st mandolin, the strip of wood that connects the soundboard and the backside is slightly damaged from where the tailpiece broke off, but the strip on the other, 2nd, mandolin is in perfect shape and has the tailpiece and decorative cap already attached.
    I guess I have 2 main questions.
    1. What is the type of wood used by Martin in 1948 for their soundboard, is it solid or are there multiple layers, and if it is multiple layers then what types of wood or veneer were used.
    2. Could the undamaged strip on the 2nd mandolin be removed and replaced onto the one I'm restoring, 1, without damaging it? The crack is actually so small and doesn't compromise the actual body so just for playability a budget sake could it just be filled in with wood puddy?
    I really appreciate your help a lot. I'm really hoping I can get this mandolin back to it's original condition as closely as possible without breaking the bank. I'm attaching photos below. All of the photos of the mandolin I am planning on repairing/talking about are labeled with a "1", and the one's labeled "2" are of the one I am using for parts.
    If you believe the 2nd mandolin may be easier to repair please say so. It's in decent shape as far as having it's original equipment but the soundboard is completely cracked at the bottom. My grandfather stored it for years and forgot to loosen the strings and I'm assuming the tension combined with humidity changes caused it to break. I believe this mandolin would only need a soundboard and to have the connecting strip reattached as it has also separated from the body due to to stress, but I haven't had anyone look at the inside to make sure the acoustics are still ok. The photos of this mandolin will be marked with a 2.
    Again, thanks so much for any infor.ation you may be able to give me.

    Josh A.
    VirginiaClick image for larger version. 

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  2. #2

    Default Re: 1948 Martin 2-15 Repair Questions

    Please forgive the multiple copies of photos. Not sure how that happened and I can't seem to correct it.

  3. #3
    Registered User sunburst's Avatar
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    Default Re: 1948 Martin 2-15 Repair Questions

    Those tops were badly under-built in the tail block area and often collapsed there. Not much to do other than a new top.

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  5. #4

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by sunburst View Post
    Those tops were badly under-built in the tail block area and often collapsed there. Not much to do other than a new top.
    I believe so as well. I really wish that f- hole hadn't been broken so I could salvage the original wood top. I keep hoping I'll find a '48 2-15 at a good price with the top undamaged so I could replace it with an original, but that's unrealistic. I guess I'll have to bite the bullet and have a new one cut.

  6. #5
    Moderator MikeEdgerton's Avatar
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    Default Re: 1948 Martin 2-15 Repair Questions

    I would guess part of that was heat and humidity. That's a lot of rust on the tailpiece.
    "Bargain instruments are no bargains if you can't play them". These are the words of J. Garber.

  7. #6
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    Default Re: 1948 Martin 2-15 Repair Questions

    I believe that the important structural component that is called the tail block or end block is loose or missing from mandolin #1.

    The rib [what you're calling the strip that connects the top and back] can be repaired by grafting in new wood, but the repair will be visible, and the tail block will need to be attended to. This will probably involve disassembling the instrument.

    A really good and ambitious repairman might be able to use part of the top of #2 to replace the damaged part of #1 from the f-hole out to the edge, or whatever strategic spot seems best after careful study.

    Repairing these instruments is not really a job for a do-it-yourselfer. The skill to execute successful repairs of this type requires long woodworking experience and a much knowledge of the principles of string instrument repair and construction.

  8. #7
    Mando-Accumulator Jim Garber's Avatar
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    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by sunburst View Post
    Those tops were badly under-built in the tail block area and often collapsed there. Not much to do other than a new top.
    I had one about the same era a number of years ago and the same thing happened though not as extreme as the OP's.
    Jim

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  9. #8
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    Default Re: 1948 Martin 2-15 Repair Questions

    Even with a thin top no. 2 failed so dramatically because the back came loose from the rims and and the instrument was left under tension. I would get those strings off of no.2 if you hope to salvage much. If you want to turn one into a decent looking playable instrument you could fix the top of no. 2 with reforming, crack repair, and large surface area thin spruce patches. The rim will need some reshaping too. Not as fear free as a top replacement in terms of longevity, but definitely less expensive while maintaining original parts and finish. Less expensive too.

  10. #9

    Default Re: 1948 Martin 2-15 Repair Questions

    There is a standard violin repair technique that could be used on the second mandolin with the crushed area near the tailpiece. Very much what jasonharsh mentioned but I'll give more specifics. It's a lot of work but is a proven repair technique that will last and will not affect the tone. About 30 years ago I rebuilt a violin with a fatally cracked top using this technique and it's still going strong.
    1. Remove strings, tailpiece, etc., lay thin plastic film over the top. Then mix and pour plaster of Paris over the top to create a negative mold.
    2. Remove the cured plaster mold then carve the damaged area of the mold to the correct curvature. Now you have a mold that you can reshape the top against.
    3. Remove the back of the instrument. Lay the instrument top-down into the mold. Make some small sandbags, heat them in the oven, apply a little moisture to the damaged area and clamp the hot sandbags in place to re-form the top. Repeat the process as needed.
    4. At this point you could apply a patch on the inside surface. But extra thickness could affect the tone. The better technique that would be used on a fine violin would be this: Carve away a smooth dished area at the location of the damage. Ideally you carve down until the top is not much more than 1 mm thick in the center of this area. Create a spruce patch and chalk-fit it until there is a perfect fit. The patch can be extra thick at this point in the process. Glue the patch into place with hot hide glue. Then carve the patch down until the top is the correct thickness. If you are patching a major crack, the grain of the patch can be at a slight angle to the grain of the top to provide extra strength.
    5. Naturally you would also reglue the back, do finish repairs and string up the instrument.

    Steve

  11. #10

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by MikeEdgerton View Post
    I would guess part of that was heat and humidity. That's a lot of rust on the tailpiece.
    Yeah. While on it's journey to me, another relative left them in an unfinished basement without opening an AC/heat vent. And left the strings completely taught. If only time travel was possible..

    I actually spoke with a friend that refinished gun barrels and he gave me a really good tip on cleaning the metal. I'll share here as well.

    First remove the metal if possible or if not adequately seperate it from the wood with some form of tape or covering. Then get an SOS pad. But before using it you have to thoroughly wash all of the cleaning ingredients out of it. He swears that the fine size of an SOS pad is much better to use on metal than most other steel wool or brushes.
    He'd then very slowly and gently use the pad to scrape off surface rust, only using water if any lubricant is needed. Then use a vacuum to remove as much of the rust flakes as possible before then using a soft pad, preferably leather, to wipe the metal completely free of any remaining fragments. Then he would use a standard oil for metal and thoroughly buff it in.
    I'll admit I was horrified at the thought of taking steel wool of any kind to metal, expecting gouges of some size, but I watched him clean an old Colt revolver and the finished job looked like it was fresh out the factory.
    This will only work on solid metal though obviously don't use this method on any thin, decorative metal. But it's perfect for more solid metal like the anchors that hold the pick guard, strap buttons or the tailpiece where the strings attach.

  12. #11

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by rcc56 View Post
    I believe that the important structural component that is called the tail block or end block is loose or missing from mandolin #1.

    The rib [what you're calling the strip that connects the top and back] can be repaired by grafting in new wood, but the repair will be visible, and the tail block will need to be attended to. This will probably involve disassembling the instrument.

    A really good and ambitious repairman might be able to use part of the top of #2 to replace the damaged part of #1 from the f-hole out to the edge, or whatever strategic spot seems best after careful study.

    Repairing these instruments is not really a job for a do-it-yourselfer. The skill to execute successful repairs of this type requires long woodworking experience and a much knowledge of the principles of string instrument repair and construction.
    Yeah I'm not going to try to tackle this myself. I've been working with wood for awhile but not on the level to where I would trust myself to fix this. Thanks for the input on it though. I was hoping for some info I can pass along to a luthier. Although I'm sure they will know what they're doing it never hurts to have some ideas to pass along to them though.

  13. #12

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by jasonharsh View Post
    Even with a thin top no. 2 failed so dramatically because the back came loose from the rims and and the instrument was left under tension. I would get those strings off of no.2 if you hope to salvage much. If you want to turn one into a decent looking playable instrument you could fix the top of no. 2 with reforming, crack repair, and large surface area thin spruce patches. The rim will need some reshaping too. Not as fear free as a top replacement in terms of longevity, but definitely less expensive while maintaining original parts and finish. Less expensive too.
    I removed the strings after taking the photos. I'm still sick to my stomach that somebody would store such an instrument with strings on it, AND in an unfinished basement with no ac or heat. But the person who owned it before it found me wasn't extremely adept in anything involving more than just the casual strum of any instrument. Yeah the more I've been looking at them I'm definitely seeing that there would be less work on #2 given that it's mostly all there and just needs to be reshaped. Thanks for your input!

  14. #13

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by Loudloar View Post
    There is a standard violin repair technique that could be used on the second mandolin with the crushed area near the tailpiece. Very much what jasonharsh mentioned but I'll give more specifics. It's a lot of work but is a proven repair technique that will last and will not affect the tone. About 30 years ago I rebuilt a violin with a fatally cracked top using this technique and it's still going strong.
    1. Remove strings, tailpiece, etc., lay thin plastic film over the top. Then mix and pour plaster of Paris over the top to create a negative mold.
    2. Remove the cured plaster mold then carve the damaged area of the mold to the correct curvature. Now you have a mold that you can reshape the top against.
    3. Remove the back of the instrument. Lay the instrument top-down into the mold. Make some small sandbags, heat them in the oven, apply a little moisture to the damaged area and clamp the hot sandbags in place to re-form the top. Repeat the process as needed.
    4. At this point you could apply a patch on the inside surface. But extra thickness could affect the tone. The better technique that would be used on a fine violin would be this: Carve away a smooth dished area at the location of the damage. Ideally you carve down until the top is not much more than 1 mm thick in the center of this area. Create a spruce patch and chalk-fit it until there is a perfect fit. The patch can be extra thick at this point in the process. Glue the patch into place with hot hide glue. Then carve the patch down until the top is the correct thickness. If you are patching a major crack, the grain of the patch can be at a slight angle to the grain of the top to provide extra strength.
    5. Naturally you would also reglue the back, do finish repairs and string up the instrument.

    Steve
    This is a fantastic walkthrough.
    Just to make sure I'm understanding this correctly, the mold is used to "push" the original wood back into position from the inside and then the patch would go on the inside, and then the top would need a veneer to cover the area that was fixed?
    Also, could this method also be used to craft an entirely new top? Thanks again for the information! I really appreciate it!

  15. #14
    Registered User sunburst's Avatar
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    Default Re: 1948 Martin 2-15 Repair Questions

    For the record:
    I have repaired collapsed mandolin tops by "sandbaging" with heat, by chalk fitting new wood, and other methods. I have worked on these old Martin mandolins and have even replaced a top on a very similar mandolin with a very similar failure. My opinion that a replacement top is the best repair is based on these experiences.

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  17. #15

    Default Re: 1948 Martin 2-15 Repair Questions

    Quote Originally Posted by sunburst View Post
    For the record:
    I have repaired collapsed mandolin tops by "sandbaging" with heat, by chalk fitting new wood, and other methods. I have worked on these old Martin mandolins and have even replaced a top on a very similar mandolin with a very similar failure. My opinion that a replacement top is the best repair is based on these experiences.
    Thank you for that recommendation. I'm agreeing with this. I wanted to save the original wood but I just don't think that's a viable option anymore.

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