I am a relative beginner to turning and segmented bowl turning in particular. I have been making the bottom Of my bowls a segmented disc in 8, 12, or 16 segments. After some time I noticed the bottom of some bowls are cracking along one of the segment lines through the center l suppose to expansion or contraction of the wood. Is making the bottom with segments the wrong thing to do? Should I be turning a round disc out of a single piece of wood? My bottom segments have been typically 3” to 6” diameter for bowls up to 10” diameter so far.