Straightening warped fretboards.

[Robert Smallwood]

Hi. I have two maple fingerboards just about ready to glue on & fret (or vice versa)...but since radiussing them & putting in the dots it has rained lots here. If you've seen 'grabs' about Australian flooding that's it...anyway I knew it was coming and shellaced both boards on every surface only to find that despite that there's a longitudinal warp of just >0.5mm that is down the length of the boards the edges are lower than the centre, or the bottom appears to have been radiussed too.

I am planning to lightly sand the bottoms brush on hot water and then clamp them to a flat surface for a few days.

Is this a reasonable course of action? Is there a better way?

I don't have enough width to level off the edges.

Thanks Rob.

[Simon Magennis]

Can't really make a good suggestion about the boards as I have never used shellacked maple fingerboards.

However, it seems to me that you need to get humidity under control in one way or another. If you look in on anzlf (Australia New Zealand luthier forum) you will find that humidity control on the east coast of Oz is a perennial discussion point. Two basic approaches - brute force, meaning air con and dehumidifiers or a seasonsal approach to work with al finer work and assembly work being done in the low humidity parts of the year. The in between method is a box or a small store room with humidity control.

My immediate reaction would be to put them aside and see what happens as the weather dries out and the humidity drops. Very slightly concave on the bottom isn't necessarily a bad thing. Some makers deliberately put a tiny hollow on the bottom with a cabinet scraper to help get tighter edges along the neck as the bulk of the clamping force will be applied in the middle.

[Clay Schaeffer]

Hi Robert,
I agree with Simon. you should put both the neck and fingerboard into a humidity controlled environment (something around 45-50% relative humidity) for several days until the moisture level in the wood returns to normal, before you do any gluing.

[Mark Swanson]

And I don't think that adding any water will help you at all!