Double Bass warping fingerboard

[colorado hick]

Hey folks,
I have an early '60s meisel URB. This summer I had a full set up, with the biggest amount of work being leveling the fingerboard, specifically removing some material close to the bridge that was causing a buzz.
Doing some recording I have noticed that the buzz is coming back, specifically when i fret an 'E' note on the D string, starting about .25 seconds after I pluck it. If I have someone push the end of the fingerboard back to towards the body then the buzz goes away. I have the bridge cranked up as high as I can stand.
Bi annual set ups are out of the question, partly because the nearest bass luthier is 250 miles away. Is there anything I can do to keep the cantilevered fingerboard from warping up? The fingerboard is a non-remarkable chunk of rosewood (not ebony) and I am tempted to cut it back a few inches, but that would suck if it did not fix it. I have also considered gluing a brace to the back to keep it stable and sanding it back. I am fairly handy and have worked on other instruments but not basses much.

Thanks in advance for the help!

 

[robobass]

Have you lain a straight edge on the board before and after you did the work? If the camber is gradually increasing then it could be that the board is too thin or the wood is sub par, but more likely is that the wrong glue was used to attach it to the neck. White glues creep, and this joint is under a lot of bending force. Check the straightness of the neck/board joint. If it's off, maybe removing and re-gluing the board would solve the problem. This is really not DIY work, however. Anyone you can get to at least for an opinion?

 

[360guy]

I would caution you about jumping to conclusions on the source of the buzzing. Put a straight edge on the fingerboard and see where it's at. There should be a very slight continuous dip from the nut to the bridge end.

If you are only noticing this on the D string it might have more to do with your bridge.

Make sure the bridge hasn't shifted.

 

[colorado hick]

Here are some pics with a 24" straight edge. With one end resting at the bridge-edge of the fingerboard, and the other end resting 24 back, i can slide a .6 mm guitar pick between the straight edge and the fingerboard. And you can see the daylight between the fingerboard and straight edge.
Shaving the fingerboard more seems like it is going to make it worse long term, my experience is that once a piece of wood wants to move a certain direction then it is always going to move that direction.
any ideas for a long term fix?

 

[colorado hick]

ok, so after talking to my luthier we figured out that since it did not get better when I raised the action and it was limited to one specific note (and to a lesser extent the octave) that it was probably something else. Here is what i found, a slightly loose fingerboard. I assume this could give me a buzz so to speak? Here is a youtube video of the wiggle
http://www.youtube.com/watch?v=r4WSPBvWIM4

 

[KUNGfuSHERIFF]

That'll do it. You might be able to get away with dribbling some Titebond liquid hide glue in there and clamping it down gently for a few days. DO NOT use epoxy or wood glue.

 

[360guy]

You could also mix up a very thick batch of Knox unflavored gelatin. It's sold in supermarkets. Essentially, it is superfine hide glue.

As far as the dip goes... I think it should be continuous over the length of the entire fb. From your pictures it looks like its mostly towards the wide 1/3 of the fb.

 

[colorado hick]

I have some dry hide glue. I will mix up a small batch. I had a friend tell me to get everything nice and warm before i glue it up. I just have to find something thin and strong enough to work the glue into the separation and figure out my best clamping arrangement.

 

[KUNGfuSHERIFF]

Good man. I use the long blade on my Swiss Army Knife to get the glue into the joint and clamp with cheap 8" clamps from Harbor Freight. You may want to make cauls if you don't have grippy, rubber-footed clamps laying around.