Official Luthiers Forum!

Hi everyone, I have one burning question that keeps arising.

So when picking tonewood, people mainly look for quarter sawn wood for its stability correct? However, I have seen some pieces of back sets that are really flat sawn that show some amazing figure. I understand that they are less stable, especially woods like rosewood (correct?), but they make some amazing lookin instruments. So my question is, if I find pieces that are extremely flat sawn, is it a matter of bracing it a little heavier not to worry about warping and issues like that?

Thanks everyone!

it may work but you must never underestimate the power of contracting/expanding wood.
it can bend any brace and if the brace is too strong for it to bend. it can crack, unglue, etc.

Heavier bracing just makes it more likely to crack. The secret is to brace the plates when they are very dry.
I have built several guitars with flat sawn wood (including Brazilian rosewood), and none of them have cracked. Some of those guitars are approaching 30 years old.
I do have the advantage of seasoning most of my wood, so I can watch its movement over an extended period. If it is very unstable (i. e., warping for no good reason), then it gets discarded. Interestingly, a good proportion of that unstable wood is quarter sawn, so there are no guarantees.

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John

It's an interesting observation that comes from looking at lots of wood during different seasons.....

Case in point - 2-pieces of Oak that live in my basement..... One just sits there... It never twists, shifts, whatever... It just stays true - Hot weather, cold weather, dry, wet, whatever... Sure - I know it is reacting to the humidity and temperature swings, but it doesn't warp or shift around.... The other - In the dry winter time - it warps into a pretzel knot.. 10" of bend and twist over 4' of length. In the humid summer, it flattens back out to dead flat again... I resawed half of the 2nd board for a Guitar... and guess what - each of those pieces do exactly the same thing as their sister board half... Warp and twist like crazy when the weather changes.... Guess what - Both the stable piece and the pretzel knot piece are quartersawn and air dried.....

Which of those 2-pieces do you want for a Guitar back or side?

Unfortunately, there's an awful lot of expensive wood out there that isn't as stable as we would like... The only way you will find out is to just keep checking on it as the weather changes.... If you find that a piece of rosewood shifts your entire wood stack off sideways and dumps it when the weather changes... maybe think of using that piece for something besides Guitars.....

Thanks

I see. So it just really depends I guess. And then there are those trees that don't even grow that wide, so the middle of each board is flat saw (or slab sawn i think?) so EVEN IF quarter sawn pieces are saught after for their "stability" (which apparantly is not so true) some of the ebonies never even grow wide enough to be quarter sawn am I correct?

I have several quartersawn ebony fretboard/headplate/bridge blank matched sets. Some ebonies grow to a good size, it just takes them a while.

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Old growth, shmold growth!

I think the tendency of some boards to warp, cup, twist, etc., is a result of internal stresses that the tree acquires while it grows. I've cut thick, apparently flat boards to smaller dimensions and then had them deform because they no longer had enough overall dimension to counteract the stresses.
And I've cut and planed some slightly deformed pieces in ways that relieved the stress, and they stayed flat. You just have to watch them over a few seasonal changes to see what they will do.
Of course, you don't have this luxury when your stock comes to you already cut to basic dimension.
Different species react to different extremes, too--and different boards within the same flitch.
Remember that rift or flat sawn material tends to get wider and narrower with seasonal movement, while quarter sawn stuff tends to get thicker and thinner (but not so much wider and narrower). I think if you keep a sharp eye on your stock and only glue it up in dry shop conditions, you can do it successfully.

I also heard that when drying, to stack the lumber and put something heavy on top? Is that a good idea to keep the stuff flat while it dries?