How a wooden bowl is made
The process starts with a freshly fallen log that is still full of sap. Splits soon start at the ends as the wood begins to dry, but they can be cut away. The easiest logs to work are ones without side branches, but they donít always produce the most attractive pieces. The more gnarled and forked the log, the more spectacular the finished bowl may be, but the higher the chance of failure.
Having got the log to the workshop, I wash off any mud, which blunts the saws, and inspect it for splits. Often a log has a split in the centre which goes right through it and this will reduce the size of the bowls it will yield.
The next job is to cut the log into lengths approximately equal to its diameter, and then cut each piece down the middle, but first I check it with a metal detector (Please donít hammer nails into trees! Iíve wrecked saw blades by running into nails.). I use a chainsaw for larger logs, but some species can be split with hammer and wedges. This is quick and easy, but seldom leaves the flat surface I need. I position the cut to clear the centre of the log and any centre splits that may be present, but may ignore drying cracks at this stage. I now have two approximately square blocks, each a little less than half of the original log. I cut off a slice of the bark and sapwood from each piece, so each has two parallel flat surfaces.
If the log is small enough, I split it with the bandsaw, which is more accurate than the chainsaw and makes less waste.
Next, I cut a disc from each block with the bandsaw. The log has now yielded at least two bowl blanks ready for turning. (Larger logs may be cut into three or more blocks instead of halves).
I mount a blank on a faceplate, held with one or more screws, and then on the lathe. The side attached to the faceplate will become the top of the bowl. The remaining blanks are bagged to stop premature drying while they wait their turn. Using a bowl gouge, I cut away the surplus wood, shaping the outer surface of the bowl. This is a rapid process and sap sprays from the wood as it spins. I form a foot to the bowl.
Next, I reverse the half formed bowl, holding it by its foot in a chuck, and put it back on the lathe ready to turn the inside. This is also done with a gouge. I leave the walls with enough thickness to re-turn and fine-tune the shape when dry, and leave a small spigot in the middle. Later, when the time comes to finish turning the bowl, I can grip this spigot in the chuck.
The roughly turned bowl now has its approximate final shape but is still full of sap. I put it aside to season, which takes a few months.
When it is ready, if it has survived drying without developing splits, it goes back on the lathe, held by its internal spigot. Using a gouge, I true up the now warped and distorted outer surface and finalise the shape, making a fresh foot. I sand the outside to its finished surface, using a combination of power sanding and hand sanding for the details.
Again reversed in the lathe, I can turn the inside to its final shape with the same bowl gouge, and sand to a finish.
Often, the bowl has to be reversed yet again to finish the foot, which may not have the shape I want, or may have marks left by the chuck jaws. But now the internal spigot has gone, so it is gripped by its rim in large wooden chuck jaws.
Finally, when the wood has been seasoned, the turning is complete, and the bowl has been sanded, it is ready for finishing. I wipe on a coat of a drying oil finish such as Danish oil or Liberon Finishing Oil. I enjoy this stage as it makes the grain come to life. I wipe off surplus oil and allow it to dry. More coats, as necessary, are applied the same way. Then the bowl is put aside for the oil to harden thoroughly .
At this stage, the surface is a little dull and may feel rough to the touch. I buff the surface using a cloth wheel and very fine abrasive, often followed by moisture resistant microcrystalline wax, to leave a sheen with a nice soft feel. The bowl is now finished and ready for its new owner.
If I am making a Ďgreen turnedí bowl, the log is selected from a species that moves a lot as it dries, and the bowl blank is prepared in the usual way. Once on the lathe though, I turn the shape to completion, leaving the walls much thinner, to allow free movement and minimise splitting as it dries. I have to work fast because the wood dries and begins to distort very quickly, sometimes within minutes. It is hard to sand wet wood, so I usually put the bowl aside for a few days to dry fully before sanding. Itís often hard to remount the bowl because of the distortion, and when it is back on the lathe, it does not run true when it spins. I have to set the lathe speed very low and let the sander move in and out to follow the surface of the bowl. Sometimes it is necessary to sand with the lathe stationary. Finally, I have to true up the distorted foot so the bowl can stand without rocking.
The result is a thin-walled bowl, oval instead of round, and with a wavy rim that may be split in one or more places. It may have a textured, leathery surface where the grain has shrunk. It will have all the Ďfaultsí that are turned away when I make a twice-turned bowl. They donít have the polished appearance of my other bowls, and donít appeal to everyone, but some love their very Ďorganicí shape.