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| As the cracked, rotting logs in the author's yard show (above), painting the ends is only a stopgap measure before correctly processing a turner's stock of "well-managed" green wood. |
Turning green wood is a wet and wild adventure, but there are pitfalls to be avoided when working with or acquiring it. In this column, I will provide background information about preparing, storing and working with freshly cut wood so that you will have better success with nature's bounty.
Green wood is wood that has not yet been dried. It's actually not green in color, but rather not yet seasoned by either kiln-drying or air-drying. It can range in wetness from dripping wet (cut in springtime) to only slightly wet (cut in fall or winter). This "free" wood can come your way throughout the year, so it's best to understand how to effectively deal with what ends up littering your driveway or overtaking your shop.
Air-dried wood is much nicer to work with than kiln-dried wood. It cuts more smoothly and cleanly; the color is often more vivid; and, for us woodturners, grain patterns are more varied. I have become more selective when acquiring "free" wood. Everyone has a preference. Mine are persimmon, dogwood and osage orange. These species are not available commercially, and persimmon and osage are difficult to successfully air-dry without cracking, but they are lovely to work with, so worth the effort!
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| Cut each log into two sections, lengthwise, for bowl blanks. For best results, remove a small slab down the middle, making sure it contains the entire pith and the small surrounding cracks. After cutting to remove any early cracks, paint each end with end grain wood sealer. Some turners like to date and label the wood they save. |
Whatever you prefer, however, make sure the wood you acquire is sound. Even experienced woodturners have been hurt by a chunk of wood flying off the lathe. This happens for two main reasons: either the wood has a large, barely visible crack and/or the speed of the lathe was set too fast. Be careful when using found wood.
Before you bring fresh-cut wood into your workshop, be aware that it might contain small critters, which, if left to their own devices, will infest your entire life. Leave the wood outside until you are sure it is free from pests. I generally debark pieces that will be air-dried. If you're interested in making green-turned, natural-edge bowls, leave the bark on.
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| You can use a cardboard circle template to cut a round turning blank from a half log on your band saw. |
Most species of wood will begin to crack right after being cut, so attend to your logs as soon as possible. Keep them out of direct sunlight - cover them with a tarp or haul them to a shady spot. Some species, such as persimmon and ash, immediately begin to attract insects. On the other hand, perhaps you like wormy ash or persimmon?
Some turners have a large freezer in which they deposit choice turning blanks. Freezing the wood keeps it from cracking, retards the growth of mold and protects from insects. And, it's immediately available for green-turning. If you have only a few chunks, you could place them in large plastic garbage bags, but make sure you turn the bags inside out every few days. You'll be surprised at the amount of moisture early in the drying stage! Turning the bags helps prevent mold from growing, which can cause the wood to become spalted. Dark lines of mold create beautiful patterns in many species, particularly maple. A word of caution, however. This mold can have active spores, which will be released during the turning process. If you are not wearing proper dust protection, they can get into your lungs. Personally, I avoid using spalted wood; some turners grow it on purpose.
To make the best use of a log for bowl blanks, cut each section several inches longer than the diameter of the log to provide a bit of trim wood on the ends. If not possible, don't worry; you can use short and thick sections for a different style of bowl or for other projects.
When you're ready to process a log into bowl blanks, the first step is to mark where to make your initial cut. This decision is as individual as your preferences and the grain and configuration of each log. Cutting each log will require two cuts with a chainsaw or a band saw. After halving each log section, look for checks and cracks. Paint each end with end grain wood sealer, an emulsified, water-based wax, easy to apply with a paintbrush. Set aside the prepared sections, somewhere out of the elements.
Depending on where the wood is stored, the size of the sections, the species and the crook of your nose, these sections will take anywhere from a year to five years to lose all their moisture. To speed up the process, I remove the bark, then, if the blank isn't too large, I cut it into a round shape, using my band saw, then apply end grain sealer.
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| Quickest way to use green wood: turn a bowl while wet. Mount the bowl blank; take care with turning the outside and bottom to achieve a pleasing shape. Turn the inside and let the shavings fly! |
For an even speedier process, cut the half-log into a round shape, then mount it on your lathe to rough-turn a bowl. Screw the top side of the bowl to a faceplate, then rough-turn the bottom and the outside form of the bowl. On the bottom, turn a recess to accept a chuck, or make it flat to glue to an auxiliary block. Remove it from the screws. Mount it to a chuck or glue it to an auxiliary block, using medium or thick cyanoacrylate glue. Turn your bowl blank. Leave it fairly thick, but uniformly so. It will warp, so you need plenty of wall thickness for turning after the blank dries. Remove it from the chuck or turn it off the auxiliary block, then set it aside. I have had good results letting the blank dry on its own. Some people place them in paper bags or in shavings or coat them entirely with end grain sealer.
The quickest, most satisfying way to use green wood is to turn it into a completed bowl while it's wet. Your bowl will warp as it dries, so make sure you have time to finish the project in one session. Let it dry completely before finishing.
Preparing wood for successful air-drying is a delightful challenge. You will make new discoveries, like three persimmon logs in the back of an unheated, dirt-floor garage. I heaved them there three years ago, totally unprocessed. To my amazement and delight, there was sound wood in all of them. Start collecting now, and have fun experimenting!