Greg, I never splinter wood. 2 things that are crucial to bending statics are:
1. make sure your belly is on one growth ring. Any growth ring violation on the belly side will make it easier for splinter to raise.....as will rough wood. I make sure I have one contin ous ring on the belly and then smooth it out with sand paper prior to boiling.
2. Use a metal strap to support the belly while bending and clamping.
Do those 2 things and you will never splinter or crack.
Hope these help ya,
SJM