Well........

Its been raining here in the greater DC area for several days (or has it been weeks). I cut the two MDF boards to size for the top of the bench and picked up the 5/8" IKEA top to cut it and found...



I mean serious warped. The center the bulge is about 1/4" high (low). The MDF is fine. I suspect the nice people at IKEA oiled the top surface and not the bottom (which is the side that swelled).

I've decided to go with a third layer of MDF and laminate 1/8" hardboard all around to finish it.

Maybe the hardwood will flatten and can be used for a table. Or a bowl.