Monday, November 25, 2013

A Method For Drying Turned Wooden Bowls

A question came up on the Old Tools List concerning preventing peach wood from cracking and checking after turning. The discussion worked it's way around to Steve Russell and his method for boiling wood to prevent such problems. After the usual rollicking and rambling amongst the denizens of the porch, boiling was given the Grandstaff stamp of approval and except for occasional flare ups peace came to the peach wood thread.

During one of the bouts of commentary, a person who felt the practice was beneath the dignity of the august body in attendance, remarked that boiling was to be considered equal to the heretical practice of microwaving wood to dry it. I can’t provide any insight on boiling wood but I did do a run of bowls that I microwaved.

SWMBO worked as the Marketing VP for a local zoo. The zoo was creating an Africa exhibit to go along with the giraffe exhibit they were building. They needed multiple bowls to be used as displays in the huts to be visited by the guests. Of course they needed them within a few weeks and dear SWMBO knew that I had made her a 12” sugar maple, salad mixing bowl. With the utmost belief that Old Sneelock would pull out another miracle she said I would be happy to help.

I didn’t have carefully dried turning blanks set aside waiting for such a project. Laminated bowls would not fit in the motif. I had few alternatives. I had read a magazine article about drying wood with a microwave and decided that this was the time to try it.

I went over to Mom and Dad’s woods and cut down a cherry tree that had gotten hung up after the last storm. I cut the trunk into approximately 20 pieces varying from 15” to 8” in relation to their diameter. After splitting I had about 30 usable billets. 

I turned the first bowl that night. After roughing the bowl to about 3/4” thickness I put it in the shop microwave. Yes I know, why did my shop need a microwave? That's a story for another day. The article said that I had to use low power and short cycles. If I recall correctly the microwave was 1100 watts and I ran the bowl through 3 or 4 cycles of 2 minutes each at the #3 setting. I think that would work out to 330 watts. I checked the bowl after each run and the surface didn’t get warm. The first 3 times there was moisture escaping the bowl and condensing on the glass plate of the turntable. After the 4th the plate was dry. I finished the bowl out, sanding and waxing it like I had the salad bowl.

The next day SWMBO came home and said the bowl was very nice. Too nice. They wanted bowls that looked like they were made by hand. Despite my protests that no self respecting turner would make ugly lopsided bowls, no matter where they were,  I finished out 20 of the least satisfying, ugliest, clunky, bowls I have ever made. I still dried them with the microwave. With the usual variations the process worked. Within the two week window, after some long nights, they were completed and delivered. 

In payment for the wood following the same process I made a bowl from the best chunk and gave it to my mother. When she passed I got it back. It’s holding apples in the kitchen. Still in good shape after 17 years.

A note of caution. During the rush to make ugly bowls I left a spigot on the bottom of one that was about 2” thick. When I microwaved it I ran it a little hotter and a little longer, without apparent effect. When I remounted it to turn off the spigot, there was a 1” diameter burned hollow in the middle of the spigot. I think if I had gone another few seconds it would have burst into flame when the pocket opened to the air.   

PS. When I visited the exhibit on opening day I couldn’t help but notice that there wasn’t a single bowl in any of the displays.
I haven’t turned a bowl since. I turn handles for myself. I even use the pretty ones.

No comments:

Post a Comment