7 string bass neck through neck reset question

[max sterling]

Im looking for advice on this 7 string bass guitar. It might be an Antonio tsai. With it being made in Taiwan known for 70% humidity it's not unreasonable to see issues when it got moved to arizona aka dry desert. There were also issues due to neglect. The saddles were caked with cat hair, saddle screwes were rusted, fretboard was cracked. It was a sad sight. I didn't pay much for it,

The neck is bowed back way more than the dual action truss rods can compensate, my question to more experienced luthiers, is there a way to reset the neck?
The obvious answers to me is removing the frets, set the truss rods to neutral (yes there are 2?) And sand the fretboard flat with a 20 inch radius.

Any advice is appreciated

 

[BurstPaulFutureStradivari]

Clamps, a humid warm location and time.

 

[BurstPaulFutureStradivari]

Another option. Remove fretboard. Remove truss rod and fill in route. Route for two truss rods as far apart as truss rod cover allows. Clamp neck in flat position or with slight relief to compensate for neck wanting to back bow. Glue fretboard back on. Use epoxy glue or if you are really sure you have done things correctly high temp epoxy. This ensures the glue won't let the wood creep back into bad position from heat over time.

 

[max sterling]

Does it have a one or two way truss rod?

It has 2 "dual action" truss rods aka 2 way. They are backed out to their maximum. Just to get the neck straight.

 

[max sterling]

Clamps, a humid warm location and time.

Clamps, a humid warm location and time.

So, set the "dual action" truss rods to neutral, clamp it to a strong straight bar in a humid room and leave it until it strained out?

Just to get prper string action i put a 1/4 inch shim under the bridge. Or else the saddles would be maxed out and still have string buzz due to string action being too low

 

[BurstPaulFutureStradivari]

You could also try my last comment just leaving the original truss rod and using wood glue and see how it goes. You could redo things if it doesn't work.

 

[BurstPaulFutureStradivari]

If it is that close I would just try my first option. Find a warm humid location and use some clamps blocks and padding (for protection) to bend the neck in the proper direction. Don't go overkill on how much you bend it. After a week give the clamps a little more tightening. Keep doing it for a while and occasionally check the neck to see how it is responding. Have the truss rod with no tension in either direction.

 

[BurstPaulFutureStradivari]

Also, try a pick locations for the clamps where the back bowing is at its worst.

 

[max sterling]

Another option. Remove fretboard. Remove truss rod and fill in route. Route for two truss rods as far apart as truss rod cover allows. Clamp neck in flat position or with slight relief to compensate for neck wanting to back bow. Glue fretboard back on. Use epoxy glue or if you are really sure you have done things correctly high temp epoxy. This ensures the glue won't let the wood creep back into bad position from heat over time.

Again, there are 2 russ rods, both are dual action

 

[max sterling]

Two dual action truss rods

 

[ctmullins]

Been there done that.

DO NOT try to make the truss rods bend that neck.

Clamp it as others have said, and leave it for a week at a minimum. Heat and humidity will help.

Are you sure the rods are dual action? Is the nut removable, or welded on?

 

[BurstPaulFutureStradivari]

Do what I mentioned with the clamps. Have no tension on either truss rod. No strings either obviously. The hotter and more humid the location the better.

 

[max sterling]

Been there done that.

DO NOT try to make the truss rods bend that neck.

Clamp it as others have said, and leave it for a week at a minimum. Heat and humidity will help.

Are you sure the rods are dual action? Is the nut removable, or welded on?

Yes, both truss rods are dual action.

 

[max sterling]

Do what I mentioned with the clamps. Have no tension on either truss rod. No strings either obviously. The hotter and more humid the location the better.

I'll will have to find or build a humid environment . I understand the method, I seen it used on s warped neck. I will update when I start
Thank you

 

[max sterling]

Understood

 

[BrianM]

Try heavier gauge strings.

 

[BurstPaulFutureStradivari]

Understood

It is the installation of the frets that caused the back bow in the first place. I wouldn't go the route of removing the originals and sanding. It will be very hard to gauge. Particularly on a big neck like this. Do an internet search for fret installation causes back bow to get an understanding of that.