Flattening a warped LP

Grimace,
Did you preheat the marble in the oven first or just stick the room temp sandwich in a preheated oven which had been turned off. I think my mistake may have been pre-heating my stones first. Anyway, sounds like marble works better than pizza stones.

Well, I don't know about glass but the pizza stone trick definitely does not work at all. They probably store too much heat. After reaching room temp, the record was more notably warped than ever. I'm not really sure if I'll try the glass or just throw this one away. A cheap fix would be nice though. I think $1500 is too much for a disc flattener given how rarely I actually mistakenly buy a warped LP.

Just found an LP that sounds great(David Bowie-David Live mastered at Sterling by Robert Ludwig)but unfortunately is rippled with warps making the dynaflex nearly unplayable even with the VPI peripheral ring and center clamps. I decided I can't subject my stylus to this violent roller coaster ride and so am trying a variation on the Mikelavigne technique outlined above. I wasn't sure about the glass so I covered two pizza stones with aluminum foil(smoothly). I have preheated these to 180 degrees in the oven and will sandwich the LP until cool. Hopefully the weight of the stones and mild heat will solve the warping and the aluminum won't damage the vinyl. I have no idea how this will turn out but this was a lost cause anyway. I will post my results. Meanwhile, any comments? Will I need to reclean the LP now? Is warm aluminum toxic to vinyl somehow?