Double Bass EUB fingerboard blank- shrinkage & planing

[BassinCT]

Greetings from CT:
I'm seeking advice on preparing a pau ferro fingerboard blank prior to beginning the rough shaping. My plan was to start the EUB project this summer, but I wanted to seek the advice of those who work with this sort of thing on a regular basis.

The pau ferro fingerboard blank (4.125 x 1.06 x 36+") has been around for 18+ months. The ends of the board are still waxed. There is a some bowing: <.044" deviation measured under a straight edge where there is a bit of grain runout on the edges.

Would you give it more time to see if there is any additional shrinkage before flattening the faces? Trim the ends off first? Once I start removing material, would you recommend allowing extra time between steps to monitor movement? Any bits of advice are greatly appreciated!

 

[arnoldschnitzer]

If it was cut 18 months ago, it probably needs more time. How much time depends on the climate in which it is stored, as well as the way it is stacked. I would not work on it until it reaches an internal moisture content of 9% or less. One way to get it dry faster is to rough-cut it a bit larger than its finished dimensions, then leave it for a while. You can also sun it, but keep it turning or you may crack it. Good luck!

 

[james condino]

Pau ferro, Macherium villosum, also commonly known as Morado or Bolivian rosewood makes a very nice bass fingerboard, as well as a pretty nice sounding dreadnought guitar back and sides. Sometimes you may aso find Caesalpina ferra marketed under the same name. Keep in mind that it does cause allergic reactions in some poeple.

There is a two part article series in American Lutherie magazine last year from my plywood bass restoration workshop at the last Guild of American Luthier's convention that discusses and shows a photo sequence of me building a Pau Ferro double bass fingerboard. I often use it as a substitute for Brazilian rosewood, d. nigra. It looks very similar, handles very well, and is a pretty dry wood in that it does not have nearly the oils that some of the other rosewoods have. Hence, your sander and such will not load up withoils and resins when you use it. It works very well, is in easy supply, and you can find it with very nice quarter and grain.

Like d.nigra, it is also much softer that ebony, so expect it to wear a little faster if you are an aggressive player and slap a lot (like me!!!!).

I can also get it somewhere in the neighborhood of $8 per board foot locally! Most of what I have seen commercially available has had some form of kiln drying, so look out for irregular stress checking. The longer you can air dry it, the better. I've got some wood in my shop that is over 100 years old and you can definitely tell a difference between that and the recenty cut wood.

If you already have the wood in hand, use what you have. Whenever I buy wood in the rough form to make new fingerboards, I usually prefer at least 6/4 or 1 1/2" thick minimum. Better to have a bit extra than to be a little thin.

Good luck,

j.
www.condino.com
www.kaybassrepair.com

 

[powerbass]

As Arnold mentioned where the wood is stored is important. If I was doing this project I would store the wood (stickered flat) in a ventilated, heated part of my house/workshop but not too near a heat source and wait till summer.
Or if you are handy w/hand planes you could flatten one side taking the twist out of it, I would skim the other side, removing as little as possible. W/one side relatively flat you can see how the wood behaves over the next several months. As mentioned a moisture meter is helpful. When it comes time to work on the FB I would rough cut the width and length of the board and again see how it behaves. If I suspect the wood is not dry enough I will rough mill/cut it and store it in a cool, dark spot like a basement for a week or so then do a final milling. If the wood is reactive I would place it face down on a flat surface w/another board on top of it and clamp in down - covering the faces slows down the drying - I keep wood out of direct sunlight and away from direct heat. When it comes to milling ideally you want to remove the same amount from both sides to balance the exposure to air. It is not a good idea to say remove 1/2" from one side and 1/8" from the other - it all depends how dry and stable the wood is. When it comes time to shape the board I would thickness it down close to final dimensions on all sides, reflatten the face you are gluing down, then glue it down to the neck blank and finish the shaping.

 

[BassinCT]

Thanks for the replies! I will do some combination of everything mentioned- particularly waiting until late in the summer to proceed and then I will work slowly. I have had the blank in my possession for 18 mo., but I am not sure how long the exotic woods company had this piece in storage after it was rough cut.

My only building experience with pau ferro is on my electric 6 and I was immediately impressed with its toughness. When planning the EUB, it seemed like a good choice for the $ as it supposedly shrinks/expands less than ebony (on average) and the species isn't endangered. I will leave the good ebony to those who are making fine instruments.
Thanks again for your suggestions.
R