StratDudeDan Posted November 4, 2004 Report Share Posted November 4, 2004 so far, i've had three acoustics in as many days come to me with the owners wanting lower action and better intonation. however, i sit 'em down and look at 'em, then realize that the action is close to 3/8" at some points (and over in one guitar's case...)! holy hell what happened to these guitars?! my guesses are as follows: major neck strain from heavy gauge strings top warping forcing the bridge to pull up (lack of humidification) one on guitar, the neck heel was cracked. i repaired it and saw the situation (about 1/4"), so i was stumped. the relief on the truss rods is set all the way to a place that would practically force a backbow in most situations, so i'm clueless there. first question: what could be causing this to happen? second: how could i go about fixing this issue? thanks in advance! Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted November 26, 2004 Report Share Posted November 26, 2004 My friend has two (bought used) acoustics with the same issues (Gibson J200 & Yamaha); let me guess, the action is so high that you can't compensate with the saddle, right? (i.e. the strings would need to be resting on the bridge) I haven't measured them yet, but my thoughts are: major neck strain from heavy gauge strings If it is neck bow, a straightedge on the fretboard will show it. If instead the neck block has rotated slightly (or the dovetail joint is coming apart), then the end of the straightedge will come out at a height above the body that is lower than the top of the bridge. I've heard this is actually a very common result for people who leave their acoustics in the car on a hot day... top warping forcing the bridge to pull up (lack of humidification) If you sight down from the top edge of the guitar, you should be able to see this as a warp in the top. A crack in the heel I think is a sign that the glue softened at some point in the neck joint, again implicating hot car syndrome. You'd be very surprised how many acoustic owners are totally oblivious to this. Quote Link to comment Share on other sites More sharing options...
guitar_ed Posted November 27, 2004 Report Share Posted November 27, 2004 Question: Do the guitars need a neck reset? I ask because the question is not addressed in the opening post. Guitar Ed If you stumble in the dark long enough, you find the light switch. Quote Link to comment Share on other sites More sharing options...
StratDudeDan Posted November 27, 2004 Author Report Share Posted November 27, 2004 that's what two of them just went to the (real) luthier to have done. the third one, i just filed some string grooves in the bridge piece and put a very light set of strings on it. Quote Link to comment Share on other sites More sharing options...
AlGeeEater Posted November 27, 2004 Report Share Posted November 27, 2004 I had the smae proble mon my 70's yamaha. Neck-Warped. Turned the truss rod fixed that. Action still high Bridge-lowered the bridge-action perfect. HMMM, everytime i play a chord tho, BUZZZZ. My acoustic has a lot of BELLY WARPING. I read somwhere that applying a wet, hot rag over the belly and pushing down slightly will settle it into place, but dont try it as i might be wrong. Quote Link to comment Share on other sites More sharing options...
thedoctor Posted November 28, 2004 Report Share Posted November 28, 2004 StratDude. I repaired an old Hohner 12-string and decided to string it like a Rickenbacher with heavy-gauge first then chorus string. Of course the neck was adjusted to an accoustic relief (bow)of about 1/32" at 12th fret and a new nut to handle the reversed string spacing. A new bridge adjuster and insert should have been all she wrote. Wrong. I ran into the same problem you had and fixed it the same way. The four chorus strings had to have gutters filed in to let them sit on the insert. Acoustics (especially big Gibsons) are not anywhere near as easy to keep an action going as a flat necked bolt-on. Glad to hear I am not alone in my lunacy. Quote Link to comment Share on other sites More sharing options...
KTLguitars Posted November 30, 2004 Report Share Posted November 30, 2004 Wood and plastics are somehow very identical in material characteristics, they have one main drawback compared to most metals (used in structural relation) and that is what is called relaxation. If you put wood (or plastic) under compression or tension, over time the tension tend to disappear. This function is dependent of temperature and humidity - the higher temp. and/or humidity the faster the process goes. Cycling of temp/humidity is even worse. As the strings puts the top wood of a guitar under constant compression/bending and the back under constant tension, over years it will change the shape of the instrument and the action will end up way too high. Lowering the the bridge and readjusting the truss rod helps - but the guitar will continue the deflect. The higher quality the wood and the better the bracing - the longer it will take before the instrument needs a "total makeover". Quote Link to comment Share on other sites More sharing options...
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