Martin and Cracks

Discussion in 'Acoustic Heaven' started by Milspec, Apr 14, 2019.

  1. toomuchfun

    toomuchfun Tele-Holic

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    I have a slightly different take on cracks developing in solid wood guitars. I agree it's humidity/heat related but I feel it's rapid changes in those two factors that usually lead to cracking.

    I bought a '70 D28 in '86 from a seller who kept it in his air conditioned house all the time. The night I bought it was a very humid evening, and after buying it I took it to a jam an an open air house. It spent a few hours in a pretty humid, warm environment. Later I brought it home to my air conditioned house and sat it in my living room in the case. After about a half hour I heard a ping through the case. I found the dreaded B string crack from the pickguard being glued to the bare top (Matrin's after '84 don't have this issue). I got that repaired and it is the only crack it has suffered.

    I have 17 Martins from 1923 to 2016 and that's the only one with a crack I created myself. I humidify my home in winter but only in the 35-40% range. I've had no issues with cracking and they sound crisp and bright in that environment.

    My feeling is if you humidify to 50% in your home, and then take it to a place that is very dry and/or colder you will have a better chance of your guitar cracking than I will. Again I feel it's rapid changes that usually do the damage.
     
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  2. GGardner

    GGardner Tele-Afflicted

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    This is off topic--and I apologize--but all things being equal, is there a higher resale for short-scale versus standard scale Martins (or vice versa)? I appreciate that it's a matter of personal preference, but just anecdotally have you noticed more demand one way or another? Thanks.
     
  3. NashvilleDeluxe

    NashvilleDeluxe Tele-Holic

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    Yes, at least they did include a pamphlet with mine, which you can now download. It's called the "Care and Feeding" guide. https://www.martinguitar.com/customer-service/guitar-care/care-and-feeding-guide/
     
  4. tjnies

    tjnies Tele-Holic

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    As others have noted, cracks are most often related to a lack of humidity. That's any solid-wood acoustic, not just Martin.
    Bob Taylor has an interesting video about crack repair; he starts by humidifying it, and often that helps.

    BTW to the OP- PM'ed you.
     
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  5. stormin1155

    stormin1155 Tele-Meister

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    That's the first thing I do when repairing a crack. Nine times out of ten, as long as the crack is 1mm or less wide, and most are, it will close right up. Sometimes it closes so tight I have a hard time getting glue into the crack.

    I only use strips of wood in cracks, as Philsofriend describes, if humidifying fails to close the cracks. Most often those are cracks beside the pickguard where the pickguard has shrunk, pulling the wood with it.

    To humidify I use ordinary damp, household sponges in soap dishes. A couple of those inside the body, and place a cover over the sound hole, and within a day, the cracks close.
     
    Last edited: Apr 15, 2019
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  6. beninma

    beninma Friend of Leo's Silver Supporter

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    Looks like a really comprehensive guide. The item about hanging on an outside wall is really interesting.

    Now I am imagining if you buy a Martin at a place like GC they've lost the guide that was supposed to come with the guitar. It must go the same place all the boxes/manuals/registration certificates for their "new" pedals go!
     
  7. rand z

    rand z Friend of Leo's

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    First, I think it's very important to keep an acoustic guitar in it's case.

    I know the general thought is to keep it out and nearby to get optimum playing/practicing time.

    But, it is much better protected on ALL levels in it's case (a good case).

    I once bought a Martin on ebay and it was pictured next to a woodstove. It never occurred to me at the time but it was so dry that careful, heavy humidification couldn't save it... and, it eventually caved in on me 7 years later.

    Now, I keep a close eye on all of my guitars, acoustic and electric, for little signs that can become problems.

    And, I keep all of them, including the electric's, in their cases. The only exception is the one that I'm playing at the moment.
     
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  8. Route67

    Route67 Tele-Meister

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    I completely agree with this; even though I live in a (usually) mild climate, I no longer view my lightly built acoustic guitars as separate entities from their hard shell cases; whenever they’re not in use, they’re always kept in their “home” and out of the sun.
     
  9. toomuchfun

    toomuchfun Tele-Holic

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    Well, it's more to do with size than resale. 0, 00 and 000 size Martin's are short scale (24.9) with dreads, OM's and Jumbos long scale (25.4). Exceptions are the M designation which put's a long scale neck on the sizes that are usually short scale. Other exceptions are artist models like the Tim O'Brien 00-18 with a long scale and you can custom order too. I think dreads still command the higher resale, especially from the mid '30's thru '64 (old factory built) and rosewood models until IRW replaced Brazilian in '69.
     
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  10. GGardner

    GGardner Tele-Afflicted

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    Thanks. I have vague notion of someday buying a used D-18. I saw a short scale advertised locally and was wondering if I would be kicking myself down the line for not opting for a standard scale (again purely for re-sale value not my personal comfort as I'm confident in my ability to adjust to either).
     
  11. coloradojeff

    coloradojeff Tele-Holic

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    I have a '69 0-16NY and a '85 D-16A. Both bought new. Both kept in cases in Colorado (zero humidity) without humidifiers for 20+ years, moved to the heat and humidity of San Antonio for 8 years, then back to Colorado. No cracks in either guitar. None. Got a "custom shop" Taylor in SA, moved back and it cracked immediately. I'd look for an older Martin D-18. You'll never lose a nickel on it as opposed to other guitars.
     
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  12. Route67

    Route67 Tele-Meister

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    There is some info from others about older Martins with no cracks, the theory is the spruce used then was well cured & aged before use in assembly - not just a matter of newly harvested wood dried to a certain moisture content then employed.

    Even though by the late 1960s Martin guitar production numbers were high, it was still not as high as today - in the last few years it’s been roughly 100,000 per year, maybe 15,000 of that coming out of Nazareth (a guess/ can’t find that number breakdown).
     
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  13. stanger

    stanger Tele-Meister

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    The Martin pickguards pulled a crack in lots of them when the plastic shrunk over time. The teardrop design seemed to help the shrinkage for some mysterious reason.

    Those cracks are so common that repair people call them 'the pickguard crack'. The cracks really tapered off after Martin switched to a different material- the black guards- but even then, there were still cracking problems once in a while.

    One thing Martin may have done to help it was to use a double-sided adhesive sheet to stick them down instead of glue. Gibsons had a similar problem with their J-45s, which used a teardrop shape off and on, and they used the 3M sheets, which gave the guards a little flexibilty. It's the same adhesive 3M sells in a spray can; their high-tack 99 adhesive.

    Gibson quit using the sheets and began buying pickguards that were pre-sprayed with the 99, covered with a slip sheet that pulled off before the pickguards go on the guitars. The adhesive is what gives the guards some mobility, not the plastic sheet it came on.
    The sheets did create a small different problem, though. They don't shrink, so over time, they could be exposed as a little line of very sticky glue around the guard. The glue can be dissolved with mineral spirits, which doesn't harm the lacquer finish, but it takes elbow grease to get the adhesive off, and it has to be totally removed from the top. If the residue isn't completely wiped off, the spirits evaporate and the stuff becomes sticky again, expect over a much larger area!

    I expect Martin did the same thing, as the crack is rarely seen nowadays. But even the best wood and construction can't stop a top from cracking occasionally, especially if the guitar is in a dry climate.

    All wood shrinks over time as it loses moisture and oils. The shrinkage can be planned for, but it doesn't always happen in a predictable way. That's one advantage the new torrified tops have- all the moisture in the wood is cooked out of it in a kiln, so the wood is already 80-years dry when it becomes a top.

    regards,
    stanger
     
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  14. toomuchfun

    toomuchfun Tele-Holic

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    Until 1984 Martin glued the pickguard to bare wood, then finished the top. The pickguard material expands and contracts at a different rate than wood, and glued to bare wood creates stress that results in the wood cracking.

    In '84 and onward, a finish was applied before the pickguard was glued on. The finish allowed the pickguard to move on the finish enough to reduce the stress during expansion and contraction, reducing the chance for the wood to crack.

    Adhesive sheets on pickguards may help a little more, with 2 surfaces that can "slide" with expansion and contraction, but gluing to bare wood is the major cause of pickguard (sometimes called "B string cracks" because that's where they usually happened) cracks on older Martins.
     
    Last edited: Apr 17, 2019
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  15. beachbreak

    beachbreak TDPRI Member

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    A few holes punched in the baggie holding the sponge, not the case. Sorry, poor wording.
     
  16. idjster

    idjster VERY grateful member Silver Supporter

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    I have a Martin D15M that I've had for a number of years with no issues. I also have a Norman B20-12 that I bought in 1971 and it is pristine as well. My trick is to keep them in the cases if I'm not playing them and try to keep them in stable humidity. The Norman has been all across Canada with me and has been played in almost every province and still looks great. Perhaps the thinner top might be the issue?
     
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