The following is for mature audiences only.
A week and a half ago I rescued some "road kill" wood from a road widening project. I cut the logs to length, cut a generous pith section from the center and sealed the ends with Woodcraft end sealer.
10 days ago I rough turned 6 dogwood bowls and 3 red cedar bowls to approx. 3/4 in. thickness and boiled them for 1 hour after the boiling started. After boiling I left them out to drip dry for a couple of days before bagging. The next day 3 of the dogwood bowls had developed cracks of 1/4 to 1/2 inch. The second day after boiling another had cracks and one of the cedar bowls also was cracking. I panicked and sealed the end grain of all 9 bowls, inside and out. The cracks have not enlarged and no new cracks so far. That day I turned more bowls and promptly sealed the end grain and did not boil. These were 4 dogwood, two cedar and two poplar. After a week none are cracking. Five cracked bowls would be insignificant to a production turner, but to me with only a couple of dozen bowls a year, 50% cracks is significant. Another problem I have been having with boiled bowls is mold growth, including the first dogwood bowls of this series. None so far on the last batch. Maybe I need to import 50 gal. of that Texas water. I have been boiling bowls for a couple of years with an occasional crack and a lot of mold. Perhaps I'll try the sealing for a while.