I bought this 370/12 secondhand and it had some neck bow, >1 mm, doesn't sound like a big deal, but big enough to make a 12string really hard to play.
After reading every advice I could find I decided to try to repair it myself. First I removed strings and all three pickups (I read that it's okay to bend the truss rods, but I just haven't got the nerve to do it), then removed truss rods. It was very easy, and there was no problems with masking tape, it stayed glued to the rods so i didn't bother replacing it with heat shrink. Neck bow was exactly the same even without strings and rods. I tried to make sure that rods are straight, but it wasn't easy, I looked hard and one moment you think that it is just very slightly bent and then it looks dead straight.
Next I applied lots of ultra-thin superglue, 2 or 3 grams, until it just flowed out of neck. Of course I was careful not to stain the guitar finish.
Then i put both rods back, it was harder than removing them because glue obviously made holes somewhat smaller in diameter. After restringing guitar began a daily process of adjusting the truss rods. Always prebending and no more than 1/4 turn once a day, it took about ten days.
Now the neck is perfectly straight. Repair is done. Maybe I just got lucky, but it was very easy to do, and I am no guitar tech, I never even adjusted a truss rod before.
Unable to get my 620's neck straight...please help
Moderator: jingle_jangle
Re: Unable to get my 620's neck straight...please help
Ashot, great work and thanks for writing up your success. The bow had probably been there for quite a while to stay when the strings were off and the rods out. Hardening the maple with the glue allowed the rods to finally work and they are now doing what they were designed to do. Great work. Welcome to RRF, too. 