ROUND IS GOOD

©Marty Kaminsky, 2003; revised 9/03

When I started turning, any bowl that escaped the trash was a great bowl. I’d turn whatever wood I could find, wet, dry, half rotted – you name it. I was totally satisfied with the oval bowls that usually resulted. Satisfied? I was way past satisfied; I was thrilled. For a while. Eventually my standards increased. I started wanting bowls that were round and didn’t rock on the countertop. So I started roughing out bowls, leaving them thick-walled, and putting them on the shelf for five or six months before turning them to the final thickness and shape. I’d get some (great) ideas and turn the rough bowls, but six months later I’d have lost my enthusiasm for whatever idea I had earlier found so compelling – if I even remembered what I had in mind. I needed to find a quicker way to dry my vessels.

I looked into a variety of ways of drying. Various approaches to air drying all take a long time. Microwaving seems like such a bother. There’s freeze drying – don’t know much about it. Boiling is supposed to reduce drying defects and drying time, but it’s another big bother and still takes about three weeks to dry. Then there’s “double cooking” – a combination of microwaving and oven cooking. This is supposed to get you from wet to dry wood in a day. Another variation is boiling plus double cooking, providing a minimization of defects along with one day drying.

For further information on these drying techniques try the following web sites:

Microwaving: http://homepages.ihug.co.nz/~rhaslip/Rex/workshop/microwave/microwav.htm

http://mgorrow.tripod.com/microwave.html

Boiling:

www.woodturningplus.com/New%20Page/e-store%20logo

Boiling, double-cooking:

www.woodturningplus.com/drying_green.htm

I haven’t tried most of these methods – I wanted something quick and easy, and none of these qualified. Perhaps they’re excellent methods with some advantages over my approach, but my method is very easy and very fast.

Drying box

I dry my rough turned bowls in about three to five days in a heated drying box. You’d think that force drying at this fast rate would result in a lot of cracking. Well, sometimes I get cracks, but not nearly as often as I would have thought, and, in fact, not as often as I used to get when I air dried my bowls for six months. My theory is that with this method of circulating hot air, I am drying the wood more evenly than air drying.

Drying box hanging from the ceiling with the lid open. Notice the winch in the upper right, and the 4” hole in the end of the box.

Drying box hanging from the ceiling with the lid open. Notice the winch in the upper right, and the 4” hole in the end of the box.

My drying box is 21” x 21” x 48”, sheathed in ¼” plywood (except for one end which is ¾” plywood), and built on a frame of 2” x 2” lumber. It’s insulated on the inside with ¾” blue Styrofoam (available at lumber yards and home improvement stores). A space heater is mounted through a hole in the ¾” plywood end, and there is a 4” diameter hole in the opposite end. Most space heaters will due – it just needs to be the type with a fan. The lid is hinged and has sash latches (which are probably totally unnecessary) to provide a tight closure. Soft insulation foam is used to seal around the space heater and the lid. I used pressure sensitive adhesive foam tape for the lid seal and somewhat firmer foam stapled around the heater.

My space heater has an internal thermal cut off that turns the heater off at 110 degrees Fahrenheit – this seems just right. It seems comfy for any resident worms, too. They’re alive and kicking (squirming?) after going through the treatment.

Heater end of drying box.

After rough-turning my bowls to about one inch thick I weigh them and write the weight of each on the bowl. The bowls then go in the box, the heater is turned on, and I weigh the bowls (and record the weight) each day. When the weight stops changing, they’re dry.

My shop where I use the box is dehumidified. If your shop isn’t, this may change the amount of time that it takes to dry your blanks.

I’ve found that my box is bigger than I need – It’ll handle a lot of bowls, but I seldom have more than three going at any one time. If I were doing it again I’d probably make it half the size. I have my box rigged up on a pulley and boat winch system so that I can raise it to the ceiling to get it out of the way when it’s not in use.

I’ve been using my box for about two years now, and I’ve found this easy and inexpensive addition to my shop most useful.