Anyone ever use an oven to reduce moisture in blanks?

[john patrick]

I have a bunch of bowl blanks that seem to be hovering around 12-13% moisture after some years. Since I don’t have a kiln and these are too large for my microwave, am wondering if anyone has tried a cool oven to get them down to 10% before finishing. Thanks!
John P

[Paul Williams]

Yes, I turn it on pre-heat until it gets to 100 to start and turn it off and let it sit in the oven until it has cools down. Then repeat. If working good I go to 120 but never above. Now for the rest of the story as Paul Harvey used to say. I have also used the oven to hurry along finish cure when up against a time commitment. One day I finished a small bowl with either walnut oil or poly and left it in the oven as it cooled down. While I was down stairs my wife decided we would have pizza. She didn't see the bowl and the pizza shoved it to the back of the oven. No fire and 350 degrees for many minutes resulted in a deep brown tint to the finish. I think I posted a photo soon after it happened. If I had a lawyer I am sure I would not insert words to the effect of I "do not recommend this method" and "don't try this at home."

[Robert Hayward]

I use the oven to remove the last bit of moisture from a piece of wood before it goes into the vacuum pot to stabilize the wood. Very low heat and it can take a day or two for the piece of wood to stop losing weight.

[John K Jordan]

I have a bunch of bowl blanks that seem to be hovering around 12-13% moisture after some years. Since I don’t have a kiln and these are too large for my microwave, am wondering if anyone has tried a cool oven to get them down to 10% before finishing. Thanks!
John P

I’ve processed and dried a lot of turning blanks over the years, bowl and other. I assume the blanks were cut from fresh wet logs.
Yes, you can use heat to accelerate drying but there can be risks, depending.

Some more info may help:

Are they still in log sections, cut into bowl sizes, cored, rough turned, sealed with something? Sealed with what, just the end grain or all over? Any bark?
How big are the blanks?
What wood species?
How many years have they been drying?
How do you measure the moisture content?
Have the blanks been stored in a heated and air conditioned space, outdoors, what?
Where do you live?

A picture or two might help.

[Richard Coers]

How thick are the blanks? What are you using to measure the moisture in the center? Absolutely don't use the dial on the oven to set the temperature, and as Paul said, don't get it hot.

[Reed Gray]

Air dried wood seldom gets lower than 15%, unless you live in a desert area. If the blank is over 2 inches thick, then the surface may measure in that 12 to 13% range, but the inside will be much higher. If the blanks have been stored inside a dry shop, then getting lower than 10% is possible. Getting down to 6 to 8% is only possible straight from the kiln. For air dried lumber, "one year per inch of thickness, then in the shop for 6 months or more". And this is an "at least" time....

robo hippy

[John K Jordan]

Air dried wood seldom gets lower than 15%, unless you live in a desert area. If the blank is over 2 inches thick, then the surface may measure in that 12 to 13% range, but the inside will be much higher. If the blanks have been stored inside a dry shop, then getting lower than 10% is possible. Getting down to 6 to 8% is only possible straight from the kiln. For air dried lumber, "one year per inch of thickness, then in the shop for 6 months or more". And this is an "at least" time....

robo hippy

Big chunks of green wood can stay wet inside for years. Due to the moisture gradient a measurement on the outside surface may not reflect what's inside. It's more even if sealed all over. The type of wood makes a big difference. The environment makes the most difference. That's what I asked all those questions.