I’m hoping someone here can explain something that I haven’t been able to find a satisfying answer to - why don’t traditional acoustic guitars crack? I mean obviously sometimes they do, but it seems to me like that should happen all the time. For anyone unfamiliar, the front (top) and backs of wood acoustic guitars have their grain direction running parallel to the neck. And inside, there is bracing. That bracing runs perpendicular to the grain of the top, and the bracing is typically glued to the top. Gluing perpendicular grain is generally considered a huge problem when it’s an item of furniture and it would be reasonable to expect an object constructed like that to tear itself apart in a few years as humidity fluctuations do their thing. But guitars usually don’t do that and I don’t understand why.

  • notittypicsplz@lemmy.world
    1·
    3 days ago

    Making guitar soundboards is a lengthy task. First, trees with very straight grain are chosen this means very little twist to the tree. I know of a guy not far from where i live who goes out to the block where the logging is happening and he will use an ax to split the wood and see how straight it is. Then those trees are brought back and quarter sawn, making wedge shaped strips of the tree. Each piece is carefully inspected and pieces with defects such as knots are discarded.

    The pieces then get bookmatched and hung to dry, and while wood generally takes 1 year per inch of thickness these actually are hung by clothespins for 2 years, if I remember quickly. These are then packaged and shipped after another close inspection.

    I also assume that wherever the soundboards are being used to build guitars, that they are given time to balance the humidity of the new room.

    Another factor is that the wood is very thin, and therefore there will be much less wood movement than there would be in a 2x4. Wood veneer is known for being stable for example. With such thin material you don’t end up with one side being dryer than the other, so you don’t have excess shrinkage one side over the other.

    • tehfishman@lemmy.worldOP
      6·
      14 days ago

      There’s some interesting information in here for sure. Some speculation about intentional allowances for some warping to occur, and information about how some tops are basically 3-ply plywood which is a bit more stable.

  • pr06lefs@lemmy.ml
    10·
    14 days ago

    Well if you subject your guitar to humidity fluctuations, it may well crack. Many do. My guild had a crack when I bought it, and when I moved to colorado it developed another. I have another guitar that has survived lots of changes in humidity and severe dryness without cracking. Maybe the wood was cured better, or I just got lucky.

    I keep my nice martin humidified to ~47% all the time. Maybe it would survive dryness, but I don’t want to take the chance. When they dry out it changes the way they play, being humidified properly helps keep the action consistent as well as protecting it against cracks.

    • tehfishman@lemmy.worldOP
      4·
      14 days ago

      Yeah I’m familiar with guitar humidors and things like that which are used to protect valuable guitars. And they make perfect sense.

      But I’m thinking about just regular parlor guitars, instruments that sit out in relatively uncontrolled environments and are played regularly, and instruments that are used on tours. Those instruments are subject to all kinds of chaos, and it seems like they should all be self destructing. And yeah, some do. But most don’t. And I think that’s really weird

      • pr06lefs@lemmy.ml
        9·
        14 days ago

        Well-cured wood can help. Guitars built with green wood will crack easily.

        Plywood guitars are tough - my resonator guitars are impervious to dryness, and they’re made of plywood basically.

        The other thing that might explain it is survivor’s bias - the guitars on the wall at the pub or in a mountain cabin either survive, or they crack and die. We see the ones that made it. Same thing with 200 year old parlor guitars - they are survivors.

  • bluGill@fedia.io
    4·
    13 days ago

    Every music store sells humidifiers because it is well known that if you don’t keep your acoustic wood instruments (not just guitars, violins, harps, pianos…) at a very consistent humidity year round they will crack. If you go looking for antique musical instruments you will see a lot of them with cracks. The ones that are not cracked are the ones where the owners have cared about humidity and temperature.