Great way to learn how to make a flat bow and learn how to tiller without spending a fortune. Simply look for the boards with darker piths and grain that runs all the way down the board. Piths are the heart wood lines. If they are light in color, dont get it. The lighter the color, the less dense it is. You want the densest boards you can find. A good indication is by the dark grain and deeper red. Id suggest backing with drywall tape, silk, or linen. Selfbows require a pretty good eye when tillering.Backing will give yousome protection agianst grain violations and will give you some leeway with your tillering.

Red oak is a real easy wood to work with. Don't make the best bows, lots of set and follow, and are pretty sluggish, but are great to learn with.