Neck Upward Bow on warwick streamer jazzman

[christianb]

I've had this bass for about a year, bought it at the pawn shop. It looked like new when I got it. It's my first electric one. It's a fret-less warwick streamer lx jazzman with a bolt-on neck, the neck is made of Ovangkol and the fingerboard of Wenge.
The neck has an upward bow (the direction the strings are pulling) and is impossible to fully counter with adjusting the truss rod. I've turned it as hard as I dear to, and in the end the neck always starts to make bad sounds. So now I have removed the neck from the body to have a closer look, measuring it against a table (don't have any tools) just to see more closely how it looks. I shows that it has a slight up bow even when the rod is tensed and the strings are of, and way to much up bow when left without string and rod tension, when it actually should be straight. So it's never straight, and far from back-bowing.
It's not really a big problem for me, I actually prefer to have little extra up bow since I like to play the strings with a lot of power. But now I need to sell it and thought I'd check if anyone now if there is anything I can do to straighten the neck out.

 

[Phil Mailloux]

Try to clamp a backbow into it. Take a long piece of wood like a 2X2 put a block at the bottom of the neck and one at the top of the neck on the fretboard, rest the 2X2 on top of the two blocks then take a clamp and clamp from the middle of the neck (top of 2X2 to the back of the neck).

Clamp a slight backbow into it. This will help the truss rod to turn easier and reach it's full potential. You will likely be able to make it backbow this way. If that doesn't work then you've got much bigger problems.

Don't forget to put protective material between the clamps and the wood blocks and fretboard surfaces.

 

[christianb]

to phil :
I understand your idea with bending the neck, although I don't entirely grasp how you want me to accomplish it. What is a 2x2 wood? Do you mean that I should just put the neck on top of two pieces of wood, one in each end. And a third one on top and in the middle of the neck. And then use two clamps to bend the neck?

 

[christianb]

Should I leave the neck clamped in a back bowed position for a long time? Should I have the rod loose when I clamp and tense it immediately after clamping?

 

[Phil Mailloux]

Here's a couple of pics. You need one small block on each ends to hold the long plank. See the backbow in the first pic? That's how you want to have yours. Clamp it like that and adjust your truss rod. Once you've adjusted it release the clamps and remove the wood. Check your fingerboard with a straightedge. If it's still not bowed enough, try the whole thing again. Don't exagerate the clamping part. You don't want to snap your neck either, just a small backbow.

Once you did all that, if the neck still won't backbow enough then it's stuffed and will cost you a boatload of money to have it fixed.

 

[christianb]

Ok, thank you so much for your help, very nice of you to upload pictures as well. I'll try it right away, thanks!