I brought up Black Locust in a pretty random thread on Woodworker’s Cafe:
Jon Arno agrees that “black locust is one of our most underutilized domestic timbers…and yet, functionally, it’s as good as many of the tropical species we are importing for use in exterior projects such as decking.” We don’t agree very often, so I’ll take this as a good sign.
Anyway, I’ve worked on and off with a guy who’s growing and promoting black locust (http://blacklocust.org , but the site’s out of date). He has some, but it’s early yet in his project, so I’ve kept looking for suppliers of black locust in forms other than fenceposts. It makes for a really nice deck, since the stuff is pretty much impervious to the elements. It doesn’t need pressure treating, and doesn’t shed arsenic, copper, chromium, etc.
Black locust grows like a weed – it’s considered a weed in some places – and offers the weird combination of fast growth, hard weatherproof lumber, and soil renewal (since it nitrogenates the ground.) There are some varieties of locust (‘shipmast’) that grow straight for excellent lumber, though straight locust generally also requires that it grow in a forest, where the light comes from more or less straight up. It grows across a large chunk of North America.
It’s tough to work – planing and jointing seem okay, though the grain can be strange, and you definitely want to drill pilot holes for screws. I’m hoping to work with Dave on putting together a site that explores how to work black locust, and I think that would help, but there’s not a lot of the stuff commercially available anyway.
Apparently, it used to be a popular wood up through about the 1800s, used most for outdoor projects like fences, sheds, masts, and outdoor furniture. Somewhere along the line it disappeared, except as a household tree or weed.
Seems like a pretty cool tree to me, and I’m planning to replace my front steps and back deck with it, but it’s odd to me that it’s generally unavailable. Pressure-treated’s had problems and is changing, imports of tropical wood for decking in particular seem to be increasing, and here’s a tree that has their qualities and grows here and fast, but doesn’t get much use.