drying kiln

[Mike Holbrook]

I am planing to make a kiln for drying green wood pieces.

I am wondering if turners use kilns to dry bowls, vases etc. after turning them. The strategy of the green woodworkers is to pop smaller spindles, rungs, chair legs, slats....into a kiln to remove the majority of fluid and prevent splitting and warping. The idea is the thin pieces of wood can be dried before the moisture can damage them. As I understand the strategy, it works best with small thin pieces that can be dried quickly. I am wondering if this would work with thin bowls or vases too or if the strategy is typically to use a longer slower drying process?

[Dale Bonertz]

Yes you can use it for bowls and such. I dry rough turned bowls in a kiln all the time. Kelly Dunn in Hawaii dries finished turned bowls in a kiln.

[Mike Holbrook]

I am wondering if there are any design considerations I need to take into consideration regarding the design of my kiln that will apply to bowls etc. that I might not consider from my spindle centric point of view? Obviously I need a space in the kiln large enough to hold a bowl or bowls. I suspect this means I need to design a larger kiln than I would need to hold thin spindles....

[Reed Gray]

Thickness will determine a lot. A bowl turned to about 1/4 to 3/8 inch thick, will air dry in about 10 days, even in my shop in the wet Oregon winter. With a much thicker bowl, then having a kiln may help speed the process. Same with spindles. If you are drying a 2 inch thick spindle, kiln drying is an art. Because of the thickness, there can be a lot of uneven drying and stressing. Solar kilns work very well, but are not as fast as some others. They heat during the day, and cool at night, allowing stresses to even out. A dehumidifying kiln can act some what the same way. There is the light bulb, computer fan, and freezer method as well. Even just a freezer of refrigerator which are both dehumidifiers. Vacuum kilns are another variation. So, which type are you wanting to make?

Preventing warping and cracking is another issue. You can keep board stock from warping too much by clamping them down, but left just stickered, that does not always go right. The amount of warping can be due as much to the drying process as it can be to grain orientation and species. Cracks, well, some times they just happen.

robo hippy