Did you realize the fresh stack of firewood in your backyard can be a good source of materials for woodworking projects? Woodturners, such as myself, prize chunks of green (wet) wood to make bowls because they're easy to turn and afford endless variations of grain and color. You'll find that turning green wood produces little dust and the long shavings fly like strings of wet pasta. And, of course, you'll derive a great deal of satisfaction and pride from the finished bowls.
I can provide you with the fundamentals of green-wood turning, but you'll need to give it a try before you realize all the fun you've been missing.
There are many places you can find suitable material. Look for freshly cut and split logs in your firewood stack. You'll also find green wood where there's new development, tree trimming and removal, in a local "bone yard" where trees and limbs get dumped, or where there are downed limbs following a storm.
Except for the very softest woods, which don't cut as cleanly as denser woods, most species are acceptable. Some of my favorite species are soft maple, box-elder, white oak, pecan, sycamore, walnut and cherry.
Before you begin turning, take the neces-sary safety precautions. Wear a full-face shield — not just safety glasses or goggles — to protect your face from flying chips. Never use stock that's split or has loose knots or loose bark — it could break apart while turning. Rough the bowl blank at low speed (about 400 to 600 rpm for a 10-in. bowl). Higher speeds can produce excessive vibration and even cause the stock to come off the faceplate. Sanding even green wood can be a little dusty, so be sure to wear a dust mask.
Face-grain bowls, in which the grain runs perpendicular to the lathe's axis, are what you'll generally turn. These bowls are somewhat easier to turn than round log sections (end-grain work). They also hold mounting screws far better and they provide a way to eliminate the center if the log, where splits can start to spread.
To create the blank, I start with a log diameter that fits readily onto my lathe. For instance, if your lathe has a 12-in. maximum turning capacity, you should start with an 8- to 10-in.-dia. bowl. So, from a 10-in.-long x 10-in.-dia. log, you can actually get two 10-in.-dia. bowls that are 3 to 4 in. deep.
Split the log in half using wedges and a small sledgehammer, or cut it with a chainsaw or band saw (if it has the capacity). Then cut a plywood template on your band saw (see photo 1).
I prefer to mount bowl-turning blanks with screws on a faceplate because it creates a reasonably secure mounting. You don't need to purchase an expensive chuck — virtually every lathe comes with a faceplate. For 6- to 12-in.-dia. bowls, use a 3-in. faceplate with No. 10 or No. 12 sheet-metal screws that penetrate the wood about 3/4 in. (or at least 1 in. for roughing).
I use two tools for the majority of my bowl work: a 1/2-in. bowl gouge and a 1-in. heavy scraper. A true bowl gouge is deep-fluted and quite rigid. If you are a beginning bowl turner, I recommend grinding the tip to a fingernail shape to reduce the possibility of the tool catching.
I use the scraper in the odd situations where I can't safely let the gouge bevel rub on the turning stock (because it can catch); usually on the inside of the bowl where the sides transition into the bottom. My scraper has a round-nose shape with more working surface on the left side (the tool's working side).
Because heat and low humidity can cause freshly turned bowls to crack within a few hours, you must take special precautions when working with green wood. One reliable method is to eliminate the center (the pith) of the tree or limb. If you have any concerns about cracking, place the freshly turned bowl inside a double paper bag for several weeks to slow down drying.
Another method to prevent cracking is to make a "twice-turned" bowl. Rough your bowl so the wall thickness is about 10 to 15 percent of bowl diameter. Then store the bowl in double paper bags (or apply a heavy wax coating to the bowl and store it) for several months. Finally, turn the bowl to its finished size. This method mini- mizes the distortion that occurs from working green wood because the wood is drier when you turn the second time.
Some turners combat cracking by simply turning the bowl walls to an even thickness throughout: about 5/8 in. or less. Wood often cracks due to uneven drying; this method gives the wood a chance to dry evenly.
Once you've turned the bowl, you can decide whether to sand it. Because green wood generally cuts more cleanly than dry material, less sanding is necessary. In fact, experienced turners may avoid sanding altogether. If you need to smooth the surface, you can wet-sand the work with water and wet/dry sandpaper, or you can use a hair dryer to evaporate enough moisture to sand the outside of the bowl before hollowing the inside.
My personal preference is to wait until the bowl has dried for a few weeks and then sand the bowl inside and out with foam-rubber-backed sanding discs mounted in a drill. For the outside, I mount the same foam-rubber backed disc in the Jacobs chuck on the headstock. Keep these tips in mind and follow the photo sequence — I bet you'll be hooked on green bowl turning in no time.
American Association of Woodturners (651) 484-9094 www.woodturner.org
Club member Alan Lacer is a professional woodturner from Troy, Wisconsin.