Let's say I had a choice between 1x12 for shelves and actually joining two ripped pieces of 1x8. Contrary to the initially appealing, I'm inclined to think that wider lumber tends to warp more than, say 1x6 or 8. So I'm inclined to actually go through the biscuit joining process to prevent warping.
Are my assumptions correct and the resulting approach? Basically, is it better against warping, to have two narrower plates biscuit joined or one wide plate?
You are always smart to join two narrower boards to achiever a shelf width rather than purchase the full width in one piece. The joined boards are far less inclined to warp. It is necessary to joint the matching edges to get a tight joint. Clamp from both sides. This helps eliminate a bow in the final piece. I personally like dowels. And if you use clamping dogs to keep the joints even biscuits are not actually necessary. Our modern glues are more than strong enough alone.
