wood bending steam box
need advice on a steam box. I built a steam box today, made from solid 3/4 x 9" lumber. Made it according to a youtube video and it turned out really nice. I attached the Earlex steam generator to it and fired it up to check for unusual leaks. Moisture dripped out of the bottom hole like it should, temperature reached 212 degrees and steam was coming out of the front vent holes i drilled into the door. All seemed like a sucess, was about to dance the jig and i heard cracking, then noticed the edges on top one side only start to have little seperation but no leaks, then it started to crack down the middle on the top board, and on the side. Temp at that point was still 212 degrees. So does anyone know what went wrong??? spent a lot of money on the wood so im a little bummed.. Any advice wouuld be appriciated.. Thank you.