Popular Woodworking 2006-06 № 155, страница 98

Out of the Woodwork

Woodworking Can be a Blast

Black powder fits the bill to split large urban logs.

For the past decade, I have been getting all the lumber I need for my proj ects from downed urban trees in my area that would have otherwise been dumped in local landfills, ground up for mulch or cut for firewood. I follow the same two-step procedure: First, as the tree is being prepared for removal, I make sure the trunk is cut to sawlog (not fireplace) lengths and, second, I then either haul the logs to the sawyer or tow the saw mill to the logs. After sawing, the boards are stickered and stacked for air-drying. However, last year for the first time ever, I inserted an extra and highly unusual step between cutting the log and sawing it into lumber.

Early in the year I got a call about a large bur oak that had been taken down in a nearby community. The owner was interested in whether I could convert the main trunk into lumber and then into several pieces of furniture. Without actually first seeing the log, I said that I probably could. Then I saw the log! It was about 12' in length, 10' in diameter at one end, and almost 6' at the other end. The large end consisted of multiple and converging limb stubs. A large telescoping crane had loaded the trunk, estimated to weigh 14,000 pounds, onto a tractor-trailer. It was hauled to the holding yard of a company that makes and sells mulch, the likely fate of this log if I could not find a way to reduce it to sizes my sawyer could handle. While theoretically the log could have been split lengthwise several times with a very large chain saw, as a practical matter this was not a feasible option. And because the professional tree service company that helped remove the tree was reluctant, I certainly wasn't going to try this approach either. I had no idea what to do and was close to telling the owner that this job was way too big for me.

Then, by coincidence, I happened to find a man who likes to blow things up with black powder, including blowing up trees.

He inspected the log and said that he thought he could blow it lengthwise into several mill-sized sections, even though it would be the biggest one he had ever attempted. To increase the likelihood of success, the large end with the limb stubs was removed. Still, there was a distinct possibility that the powder would simply blow the log to smithereens.

On a rainy day in April 2005, the man and his assistant, several other witnesses, and I gathered to see if the log could be blasted into usable sections. I positioned myself about 50' away with the video camera ready to roll. The log was sitting on an

by Sam Sherrill

Sam is a professor at the University of Cincinnati. He is a lifelong woodworker and the author of "Harvesting Urban Timber: A Complete Guide" (2003, Linden Publishing). Contact him at samuel.sherrill@uc.edu or visit his web site at harvestingurbantimber.com.

asphalt surface wet with rain. As the video at popularwoodworking.com shows, the first blast split the log into two halves and blew one across the slick asphalt in my general direction (click on "Magazine Extras" to see the movie). Fortunately, the angle of the blast was such that the log skidded past me instead of into me. Subsequent blasts (taped from a greater distance) parted the log into usable sections. My sawyer hauled them to his mill where they were sawed into lumber.

Today, most of the boards are air-drying in my shop where in a few months my son and I will begin fashioning them into the tables and benches the owner commissioned. My wife, who is a pen turner, turned 20 pens and 20 letter openers that the owner gave away as presents this past Christmas.

Final thoughts: If you have never worked with explosives, absolutely do not try this on your own. Regarding blasting anything, if you think you are far enough away, move back half again that distance anyway.

And, there is always another way to skin a cat, or split a log. PW

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Popular Woodworking June 2006