I clamped the top to the side of the base, as I had done before, so that the edge with the knot would be easy to work with. I mixed up some ordinary five-minute epoxy and added just a touch of black epoxy pigment. I applied this freely. After about twenty minutes I checked on it and found that in the deepest spot the void wasn't entirely filled, so I mixed up another batch and added more. After that had cured for a bit I eased the top to the floor and applied a coat of oil to the bottom side. I planned on attaching the base to the top the next day, and I wanted the bottom side oiled to keep it from absorbing moisture.
Anyway, the reason I bring all this up is not to brag, but to alert you to a great deal. Recently, we had a chance to acquire the last print copies of these five books, which were sitting, overlooked, in a warehouse. The books mainly have black and white interiors and beautiful hand-drawn illustrations. And every one offers more than 300 pages of excellent advice on woodworking projects and techniques.
If you decide upon construction lumber, you want kiln dry lumber. Green lumber will warp on you as it drys. Dig through the stacks and pick out the straightest, cleanest pieces. Generally, the boards that are sitting loose on the stack are those that other people left behind, as they sorted through looking for better. Be prepared to move them out of the way, and to dig down to the better stock. Be nice, though, and put everything back when you're done.