A check is a small crack that occurs in the end grain of the board or log. These checks can increase in size to form a crack. A crack is usually a grain separation within the grain. Any piece of wood will be checked as it dries. This is a natural occurrence, but it varies between tree species. Everyone will check; some more and some less.

From a piece of green wood (green wood is wet wood) the surface begins to dry out; as wood dries, it shrinks; The wood fiber on the outside of the wood dries at a different rate than the wood inside. As moisture evaporates from the wood, the outside faster and the inside slower, the outside wood shrinks, around the inside wood being wetter and larger; so the outside will be controlled as it contracts around the wetter center wood. Left alone, these little checks will continue to grow and render the wood worthless or firewood.

There are several methods to prevent or slow down the controls. To do this you have to slow down the evaporation process. One way is to coat the ends of the wood with wax (Anchor Seal is good), this will help, but not in all species. Does the local environment have much to do with the drying of the wood? Do you live in a cool, humid area or do you live in a hot, dry place?

The wood can be cut into various sizes for future use and then stacked in a cool, dry place with good air circulation. There will be some checking and cracking with this method, but you can usually avoid it. This type of drying takes longer and requires more space.

The best way to dry wood is to use an oven. This can be expensive, but the recovery of wood from loss due to cracks and crevices is great, and the time required to have dry wood ready to use in your project is a huge benefit. On a small scale, ovens are easy to build. They require an insulated box of a certain size, a fan for air circulation, a heat source, and a dehumidifier to remove moisture.

I recently built a small kiln where I could dry 5-6 bowls which I turned into green wood. Most bowls take 7-10 days in the oven and I usually put them in a dry place and let them acclimate for about a week. A couple of technical tips. If the dehumidifier removes moisture quickly, the wood will crack, use an on-off timer. Moisture meters will not work. Weigh the wood every day, as the wood dries the weight change will slow down. When the weight changes slightly from day to day or stops changing, the wood is dry. There will always be some amount of warping, so cut off excess wood to remove the warping.

I always like to turn the wood green. The small oven works very well for me.