Sanding a fretless board

[moles]

K, here's a question that I haven't seen any mention of.
I'm doing a defret on my J, in the middle of the Jaco Epoxy thing, just getting ready to sand/shape the first coat. I'm working with the neck off the bass ('case that matters). Would you recommend loosening up the truss before starting on that? I left it tightened to ensure that maximum epoxy got into the fret slots to fill, but I'm concerned that I'll introduce some curve into the fingerboard if I leave it tightened (and thus slightly backbowed). Then again I'd rather not have to spend that much time readjusting if I don't have to. Just for the record, I'm curious about this for when I'm dressing the board on my other fretless - it had quite a bit of wood taken out of the middle ground, and I'm wondering if it was partially because it was worked on with the trussrod tightened.
Any thoughts?

[Kael]

I tweaked my trussrod till the neck was perfectly straight before I epoxied my fretless J. My reasoning was that epoxy isn't the most flexible thing out there, so the less I had to mess with it the better. I usually set up my necks to as close to flat as possible anyway.

I held off on shaping/sanding my fingerboard untill I was done with my last epoxy coat.

[Turnaround]

You should adjust the truss rod to get the neck as flat as possible before you begin sanding it. And check for flatness frequently as you sand. Best to use radiused sanding blocks if you have them.

[moles]

Right-o then. I was presuming that the neck is in good enough shape that it should be straight with No truss rod tension on it at all. Guess that may not be true though - either way though, thats what I thought. It should be straight.
Thanks again.

[202dy]

Straight is straight. Or is it?

The important thing is to be able to get the neck straight under string tension. None of the above methods is guaranteed to make that happen. Might work. Maybe.

The only sure way to do this is to be able to jig the neck in the playing position (almost vertical)with the strings on and then convert that to work position (horizontal). Check out the neck jig at Stewart-MacDonald. Proper use of a jig will get the neck straight every time. Without the jig, chances are that the neck will never be straight under string tension. And that is the way the guitar is played, under string tension.

Why do this? A straight neck is the basic reference position. The strings can pull the neck into a gentle, controlled relief. If the bass is to sing and still have reasonably comfortable action this is a must. It also makes it easy to control the amount of mwah available.

Some may make the argument that all of this should be done after the epoxy is applied. I will not argue that point. It should also be done after the last coat of epoxy cures.

On a personal note, rather than slop some glue in the slots, I prefer to fill the slots with the same material as the fingerboard i.e. rosewood veneer in a rosewood board. Yellow glue, if handled properly, will work just fine in this application. Other choices of adhesives will also do well. I'm not a fan of the epoxy coat on the fingerboard. I've played them and do not hear a sonic advantage and don't see an economic advantage over playing over wood. I think that wood feels better under my fingers.