Roasted wood

[MysticMichael]

Originally Posted by Bruce Johnson

Last year, I built a batch of six of Mike's necks at the same time. They were all the same dimensions and all straight grain maple. Two were roasted, two were fresh kiln-dried, and two were from a kiln-dried board that had been sitting around my shop for about ten years. It was an interesting comparison, and I kept checking their tap tones and characteristics all through the process of building them. The roasted necks were the deadest sounding, the fresh necks had the most ring, and the old necks were in between. In the finished guitars, Mike said that he couldn't hear too much difference between them. If anything, the roasted necks were a little warmer, like necks that are made from soft maple.

So to extrapolate from that experiment, would you say that, roasting aside, maple gradually becomes less acoustically lively as it ages? And if so, would that process basically be brought to a halt just as soon as the wood is finished & sealed, i.e. with tung oil, lacquer or paint?

MM

[Bruce Johnson]

Here are three necks that I finished up for Mike last night.

The one on the left is regular quartersawn kiln-dried maple with an Indian rosewood fingerboard.

The center one is roasted highly figured flame maple. The board, which made this neck only, cost about $250. It's a "match" fingerboard; it was sliced off the back, routed flat, then glued on top.

The right one is also roasted figured flame maple. It's a bit lesser grade, and came from a larger board which I got four necks from. So, the cost per neck for the wood was about $125.

You can see the distinct tannish-brown color of the roasted wood.

[CH Design]

Maybe I'm shopping in the wrong places. I think I paid about $12 for the roasted ash

[Bruce Johnson]

Originally Posted by MysticMichael

So to extrapolate from that experiment, would you say that, roasting aside, maple gradually becomes less acoustically lively as it ages? And if so, would that process basically be brought to a halt just as soon as the wood is finished & sealed, i.e. with tung oil, lacquer or paint?

MM

Yes, that's essentially what I've seen. A maple board that's been sitting unfinished for 2-10 years will dry down to a lower moisture content level, and become less acoustically lively. By that, I mean that if you rap on the board, it will be less "crack" and more "thump". If I build a neck out of that aged board, it will tend to make the bass sound a little warmer and less bright, assuming that all else is kept equal. If I properly seal up that neck with finish (as all necks should be), then it should stay in that same moisture level and tonal character, no matter where I take it.

As far as I can tell, a maple board that's been air drying for years doesn't lose any significant amount of strength. As it dries out, it becomes slightly lighter and easier to split. The lowering moisture changes its internal damping properties, which changes how it sounds when you rap on it or flex it in an instrument structure. But an old board still has most of the same strength and impact resistance.

Note: I'm in Burbank, CA, which is hot and dry as compared to most areas of the country. When I store boards and build necks from them, they will end up with lower moisture content than if I were building necks in other places, like the Everglades or Seattle.

How long it takes the wood to dry will depend on how thick the board is and what climate you store it in. I build my Scroll Bass necks as 3-piece laminates of hard maple. I buy it as kiln-dried 6/4 stock and rip it into strips 1 1/4" square. That size dries out fairly quickly. I store those strips for at least a year before I use them.

For comparison, the roasted maple is heated and cooked to take it down to a much lower moisture content than it could get to by kiln and air drying. I don't know that much about it, but in the process, the wood's cellular structure changes and fuses together in some ways. This gets rid of most of the internal stresses and leaves it much less likely to bend or twist over time. But there is a price to be paid for that stability. The board ends up as I've described: a hardened outer skin over a soft, weaker core. Some strength properties are lost. It's a tradeoff.

That's why my experience with roasted maple so far leads me to the conclusions:

For a straight grain maple neck, I'd rather have normal kiln and air dried wood.

For a highly figured maple neck, the roasted maple is worth the extra cost and the loss in strength, in exchange for better stability.

[MysticMichael]

Thanks, Bruce. That's interesting stuff to know.

At present, seven of the eight bass guitars I own has an all-maple one-piece neck or mostly-maple laminate neck (the other one has an all-walnut neck). To the best of my knowledge, they were all constructed of relatively new or minimally aged wood - which is actually OK with me. I like my instruments to sound alive...and fortunately have had no problems with warping or twisting.

It kind of makes me glad that I don't suffer from the figured-wood fetish that seems to affect so many bassists. Therefore I'm able to resist the temptation to invest in instruments with curly maple or birdseye maple necks that might need to be roasted.

MM

[mikebpeters]

Pete, I have a local supplier (very cagy about his source) that has roasted birds eye. He occasionally gets AAAAA grade pieces and I see one of those making a fingerboard some day. Anyway, after having seen the pieces my research showed that it isn't the temperature so much as the pressure that is required to 'roast' wood.

[reverendrally]

Interesting stuff. Personally I hate the look of it, but it's great to know the science behind it all.

[pilotjones]

Originally Posted by mikebpeters

Pete, I have a local supplier (very cagy about his source) that has roasted birds eye. He occasionally gets AAAAA grade pieces and I see one of those making a fingerboard some day. Anyway, after having seen the pieces my research showed that it isn't the temperature so much as the pressure that is required to 'roast' wood.

What knowledge or evidence do you have that pressure is involved?

[Bruce Johnson]

Yes, it's my understanding that both heat and pressure are involved in the process. That's why it's expensive, and why the process is mostly done on smaller boards. The heating takes place inside a pressure tank, and the cycles of heat and pressure are carefully controlled.

This "roasting" process is still evolving. There are some companies that are doing the homework and figuring out how to do the process correctly. Their boards are expensive, because apparently the process also takes time, and they can only put so many boards into their pressure cookers at once.

Like anything else, you have to beware of cheap knockoffs. There are guys who see big dollar signs in their eyes, because boards that are tannish color and smell like they are burnt, can suddenly be sold for much more money than plain boards. Early on, Mike bought a couple of "roasted" maple boards for fairly cheap on ebay, and they turned out to be junk. Well, not really junk. They were just normal maple that had been stuck in an oven and made brownish. We called it toasted maple. The browning didn't go all the way into the board, and there wasn't any obvious structural change to the wood. Just some guy making money. So beware. As Roasted Maple Necks become more of a fad, there will be more of this. Any day now, we'll be seeing cheap import guitars showing up with Roasted necks. They'll shape and sand the neck out of normal maple, splash on some secret Barbeque sauce, and pop them in the toaster oven for a few minutes. Does that qualify as Roasted Maple? I don't know.

For the last year at least, Mike has been buying all of the roasted boards from one source, and they have all been very high quality. We had, I think, two boards that had large knots hidden down inside them, but the supplier replaced them both with no problem. I don't remember who that supplier is, and I'm not sure if Mike wants to put that info out on a forum. From what I understand, the supplier is booked up, and sometimes there's a waiting list for his boards. You'll have to do your own digging.