back bow at body joint

DDP

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I recently bought a trad plus and it played beautiful when I bought it in Southern California. I brought it to Asia with me where I work, over the last week or two it started buzzing real bad. I discovered a pretty severe back bow with the strings hitting the 7fret when I fret the 1st and 22nd. I adjusted the neck, got just a slight gap at the 7th but still major buzz. I took it into a recommended guitar builder, he checked it, said the neck relief was good from the nut to the 16th fret but at the body joint the neck is arched backwards. He also noticed the bridge is collapsed. He said he can remove frets, sand the fretboard flat and refret, but if I take it back to the US it will probably return to its original shape. Anyone have ideas what to do? Im hoping against logic that a few more weeks here in Thailand will get the neck to settle back into shape? Not that it would make that big of a difference but I have it strung up with 13s...
 

rockstar232007

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There's your problem. You're using too heavy of a string gauge.

The recommended string gauges for LPs (short-scale) are between 10-11, because anything higher, and there is higher tension/pressure put on the neck. Especially at the joint. This is usually referred to as, "neck-rise".
 

DDP

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but wouldnt the higher tension pull the neck forward rather than back?
 

rockstar232007

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but wouldnt the higher tension pull the neck forward rather than back?
No. What's basically happening is, the higher forward tension/pull of the strings, and the backward pull of the truss-rod is basically causing the neck to compress at the joint.
 

DDP

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hmm ok. I just restrung it with 11s, and then rechecked relief. major backbow again, all strings wee fretting out on the 7th. I loosened up the nut a little to give some clearance. I think its buzzing worse than before, but Ill give the neck a chance to settle down with less tension. Hopefully in a few days it will be better. Thank you
 

pfox14

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I think you have multiple problems. Definitely use lighter gauge strings. I would recommend 10s. You might want to raise the action up higher to give yourself some more clearance. I would also increase the neck relief to compensate for the back bow at the heel. If all that doesn't work, then I would get the fingerboard re-leveled and re-fretted.
 

emoney

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How about some pictures of this, and did the guy say "why" it's doing this only in Thailand?
 

DDP

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pics wouldnt really show much... maybe if I hadnt left my good camera on top of a taxi in china and then superimposed a straight line.... He didnt know why it did this after I got to Asia, maybe humidity? Maybe it was the 13s I had on it... I dont know, the weird part is I always played my old Epi with 13 and it was never a problem. I did move the action up a bit higher, it helped somewhat with the buzz but far from perfect... I think Ill give it a few days, if there is not much of an improvement I will change out to 10s... or maybe Ill just pick up a pack tomorrow and throw them on. I will say that the 11s feel like playing a slinky to me, not sure if thats good or bad but it does sound thinner, at least acoustically.
 

onegoodtrick

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"He also noticed the bridge is collapsed."

I just come over to this section of the forum to learn and leave the coments for those that work it daily.I am assuming the bridge has been replaced but see no mention that was addressed.Man,13's.That has to be adding an additional 40-50 lbs. of pull.I play 11's/wound 3'd,and need to reset TR and intonation when going back to 10's.

I do have direct experence with neck rise and it did scare the bo diddly out of me on several vintage set neck acoustics.Altitude and rapid humidity swings seemed to be the common variable,and the solution which brought these necks back in line FOR THESE GUITARS was as follows

- backed off the TR just 2 flats
- humidified the CASE and guitar slowly over the course
of a couple weeks to approx. 40%(was at low 20's)
- backed off the TR another 2 flats and brought the RH in
the case up to 45% for about another 2 weeks
- time seemed to do the trick and at about a month in the
necks had settled back enough to adjust the TR into a
reasonably accurate relief.The foward section of the necks
had raised slowly over time to meet the drop at the heel.

These were Hog necks and other than being neglected as to keeping the RH in correct range were in excelent condition - fretboards oiled,etc.
This was just my experence and I'm not recomending you try this without confirmation from an actual LUTHIER,but it did work for me.I would suggest that you take your time,don't get anxious to see results and over medicate with humidity - wood seems to require a fair bit of time to move
back to its' happy place. I wish you a good luck. Cheers.
 

DDP

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I have not been able to replace the bridge yet, I hit up a few stores here. All I found was metric bridges, genuine gibson for over $100 or some brand I havent heard of with titanium saddles for almost $200. Sometime this week I will go out hunting again. I changed out to 11s and wow its like playing nothing... Im just so surprised I have always had 13s on my epi with no problem, but 13s on a big 50s neck changed everything... The past few days I had to loosen the truss rod 2 flats, it seems quite a bit better... I had to raise up the action a bit but the D and G string are still buzzing pretty bad. Looking up the neck the A D G and B do look really flat, and the low E sticks up quite high, almost like the saddle notch wasnt made deep enough. Lack of humidity is NOT a problem here!
 

greenhorn

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the D and G are buzzing the worst because the bridge is collapsed.....
 

bruce bennett

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I'm gonna bet that your running into a humidity issue..

I have a friend whose 1974 les Paul standard plays awesome... in chattanooga TN

BUT ... get anywhere near 50-70 miles from the ocean, and the neck bows back and the strings lay tight to the frets.. until 48 hours AFTER he gets home. then its goes right back to playing perfectly..

the fingerboard on a Les Paulis unfinished and therefore open to the elements.. and if it absorbs any moisture, it tends to bow backward..( because the side of the wood that absorbs the moisture will swell whiel the back side thats glues to the neck won't) and it will stay that way until it releases that moisture into a climate that is dryer than the one it absorbed the moisture in..

which is why the luthier told you it will likely go back to it original position as soon as you go home. hes right.

once you get home, you can put a couple of coats of seal-a-cell by General Finishes on the board, and it will greatly slow down the absorbtion rate so that a 2-3 week trip into a high humidity enviroment will be "survivable"
 

DDP

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Bruce, thats what I figured... my problem is... well one of my problems is that my trips here are usually measured in months, not weeks. My last trip was 8 months with only one week back home. I think Im here for another long trip. Actually I hope to move into my apartment tomorrow.
 

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