Glueing V-grooved pine tongue and groove boards
I made some kitchen cabinets for a friend's cottage and made the doors by glueing up V-grooved knotty pine tongue and groove 5-1/4" boards, as per her wish.
I supported the glue up with 3/8' thick, 1" wide pieces running perpendicular 5" from the top and bottom of the doors. I did this to hopefully prevent possible warping of the doors. I made the cabinets around Christmas time and gave them to her to finish.
Two weeks ago I installed the cabinets at the cotttage. To my horror some of the doors have warped anyway, the worst one was just shy of 1/2".
I offered to make new ones but I want to make sure that the new ones will not warp. Any ideas on what to do to ensure that this warping will not happen?