Woodsense: Spotlight on Black PalmComments (0)
This article is from Issue 61 of Woodcraft Magazine.
Shake hands with a weird wood.
Technical consultant: Larry Osborn
Compared to other woods, about the only similarity one can claim is that black palm comes from a tree. Neither a softwood nor a hardwood (technically, it’s a grass), it displays no growth rings, has zero knots, shows no medullary rays, and exhibits absolutely no figure variations such as curly or quilted. And because the trunk is branchless, even crotch figure is nonexistent. Unlike other trees where the best stock is found in harder heartwood, the best black palm boards come from trunk’s hardened outer layer. Surprisingly, this section contains no sapwood.
Examine a block of black palm, and you’ll find dark chocolate quill-like streaks blended into a tan background. For this reason, some have referred to black palm as porcupine wood. As you rotate the block, you’ll notice that the appearance is virtually identical on all four sides, making any discussion of face grain versus edge grain meaningless. If this species (Borassus flabellifer) hasn’t already provided you with enough surprises, you’ll discover black palm’s real bombshell when you study its end grain. It appears that someone painstakingly stippled tiny black dots onto a tan background, as shown below. This look is completely unlike anything you’ll see in other woods. But except for the colors, the dotted pattern is similar to what you see at the cut end of a piece of bamboo.
This relationship to bamboo isn’t coincidental because it, like black palm, is a monocot. Both are members of the monocot family (flowering) plants that sprout with a single leaf. (Most hardwoods are dicots, which produce two-leaf seeds.) Besides bamboo, other monocots include grasses, banana, rice, wheat, and corn.
Black palm can soar up to 100ʹ tall, with a trunk diameter sometimes reaching 3ʹ. Because only the outer portion of the tree produces usable wood, the sizes sold in the U.S. are typically restricted to spindle squares and narrow boards.
It’s a fact that…
Black palm is widely planted as a crop, and every part of the tree has a use. These range from the edible nuts, to a laxative, to a sugary sap called toddy that’s fermented into a beverage called arrack. The palm leaves are woven into mats, baskets, fans, and can even be prepared as paper, with the veins serving as naturally ruled lines to guide writing.
History in woodworking
While we must content ourselves with narrow pieces, much larger sizes are accessible within Indian and Asian forests containing the tree. Here, the wood has served as rafters, fence posts, or parts for building boats and furniture.
Today, in the United States, black palm is more frequently used for knife scales, tool handles, boxes, pens, pool cues, and other small turned objects. Strips of end-grain black palm make eye-catching inlays.
Where the wood comes from
You can find it throughout south and southeast Asia, including Bangladesh, Cambodia, India, Laos, Myanmar, Sri Lanka, Thailand, and Vietnam. That said, it’s somewhat difficult to pinpoint the original natural habitat of black palm because people have long taken an active role in spreading its range through cultivation. For that reason, the tree is not currently–nor is likely to become–endangered.
What you’ll pay
Even the largest pieces of black palm that you’ll encounter are fairly small, so it doesn’t make sense to look at cost per board foot. Instead, you’ll find the wood sold at a per-piece price, such as turning squares for pen blanks, knife scales, and so on.
Expect to pay about $2.60 each for an unstabilized pen blank; epoxy-stabilized blanks cost nearly twice as much. You can find a 11⁄2 × 11⁄2 × 12" turning square for $6.00, and a 3 × 3 × 12" turning square for around $27.00. A 3⁄4 × 3 × 36" board may set you back $35.00; a 1⁄8 × 3 × 24" piece, $18.25. If you’re willing to do some resawing at the bandsaw or tablesaw, you'll save several dollars.
You can also purchase black palm veneer from an online source in 1mm and 2mm thicknesses in 8 × 100" sheets. The thinner, pricier veneer costs up to $28.00/square foot.
Selecting the best stock
The overall tone of the black palm varies within a range of samples, but the darker the appearance, the greater the concentration of the dense fibers. In addition to the visual look, you can also drop samples into water. Denser pieces of black palm will actually sink. Even though available boards may be narrow, you can edge-join those having the same color and density to achieve wider workpieces. The joints may be barely discernable.
Working black palm
To visualize the vascular structure of black palm, think of extremely brittle black toothpicks tightly bundled together and encased with a relatively soft tan glue. The difference in density between those components helps explain the challenges of working with this wood. The tan plant tissue (parenchyma) doesn’t provide great support, so the hard dark fibers erupt in splintery tear-out or can pull out, producing a pock-marked surface. This defect may appear on surfaces that are ripcut, jointed, or surface-planed. A sharp chisel cutting at an angle can produce a clean face, and crosscuts with an 80-tooth, 10" blade in a mitersaw should yield smooth, clean ends. The wood sands cleanly, but use a sanding block to ensure a flat surface.
When turning, wear a face shield and use extremely sharp tools of high-speed steel with a particularly light touch. Because black palm can tear out at the lathe, stabilize the wood using thin cyanoacrylate (CA). To get a better turning result, send your blanks out to be stabilized with acrylic monomers and polymers that are forced into the fibers under pressure. (Visit wooddynamics.net; expect to pay $3.00 per pen blank).
Finally, finish black palm with lacquer, polyurethane, friction polishes, or CA. Preserve it with clear shellac or sanding sealer.
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