Methods of drying wood bowl blanks
I turn a lot of Pacific Madrone. This wood is generally not used because it cracks and wraps wildly as it dries. One artist that uses the wild movement to his advantage is Christian Burchard. Christian turns green madrone very thin (in the area of 3/32") and lets his baskets move as they dry. I turn functional bowls and want my wood stable. After I rough out my green turned bowls I boil them for a couple of hours in my stainless steel tank. After the water cools down some I take the bowls out and air dry them as I do other wood. I do watch the bowls closely for about 6 weeks. Some burls like to crack and some are easy to dry. I have also used boiling on several fruit woods like apple and cherry. Cherry sap wood is very prone to cracking as the bowl blanks dry. However, I quit boiling cherry because the boiling clearly takes out the anti fungal elements in the wood. Boiled cherry “pin” spaults almost immediately and I don’t like this spaulting.
I have not tried this method of soaking wet wood in alcohol to accelerate the drying. In talking to friends, they have taken wet wood and made it dry in a very few days by soaking it in alcohol and then letting the alcohol evaporate. I have two concerns with alcohol. First, it is very flammable and accidents happen. Second, in talking to two friends from England, both said that alcohol drying makes the wood harder, and thus more difficult to finish turn.
Soaking in soap
I have talked with several people who have taken green turned bowls and soaked them in soap water. After soaking the blanks they are taken out and air dried. Again, I have no personal experience with this method. My only concern would be with possible soap residue in the wood. Soap attracts water. Would the soap residue in the wood continue to attract water after the bowl is finish turned? I am not enough of a scientist to answer this.
I think this method is best used on thin projects and you would like to get some nice movement in the wood. I have used it to hasten drying of green roughed out bowls. But it takes a lot of messing around with. I used three minute cycles. I let the wood cool down between cycles. It will take several days of these cycles to dry the blank so I only use it if I have a special call for a bowl. Remember, a microwave dries the wood from inside out. If you see smoke coming out you have probably burned the inside of the wood. And if you try to dry it too quick it will end check.
There are many types of kilns. The most popular for woodturners are the converted refrigerators. These have been described elsewhere. Phil Lapp in our club built one and uses it to dry his rough bowl blanks. Phil said it takes about two weeks to dry a batch of 12" bowl blanks and less for smaller items. Phil said he turns the blanks a little thinner than if he was going to air dry them. Phil likes this kiln method. The only downside to kiln drying I have heard was from my professional friends in England who said that kiln drying wood makes it harder, thus not as nice to cut with tools as air dried wood.