Neck straigtening - this worked like a charm for me

[jakelly]

I bought a pretty nice Samick 5-string a while ago. It played fairly well when I bought it, but it looked like it needed a truss rod tweak to lessen the amount of relief. This didn't concern me, so I bought it. Got it home, and the truss rod would not pull out the excess relief. I tried shimming the truss rod nut, but that didn't help either. Even with no string tension, the neck showed excess relief. It seemed the only thing to try was to heat straighten the neck, and I had never had much success with that, but I learned of a good way.

I supported each end of the neck with a couple of tool boxes (anything will work of course). With the fret board facing up, I put three 90 watt light bulbs underneath it, spaced at even intervals (I used a couple of small lamps and a drop light). I also laid a sheet of aluminum foil over the top of the fretboard, just to hold more heat on the neck. I let it heat for a few hours (it got very hot and that's what is needed), then shimmed each end of the fretboard with a small block of wood, and clamped against a heavy board. You have to put quite enough back bow in it while the neck is still hot, and you use the clamps to control that. You need to use plenty of padding on the clamp jaws to avoid scarring the neck. Let the neck thoroughly cool while clamped. If all goes well, when the clamps are removed, the neck will spring back a bit to being perfectly flat. Then the truss rod can do its job. The heat does not hurt the finish on the neck.

[ChrisBowsman]

I've never heard of using heat to help straighten out the neck. Luckily, I've never had one that needed that much effort.