found this formula a while back: (specific heat of aluminum x volume of plate x aluminum density x change of temperature you're looking for)/ power ran a 1285 x 1120 mm aluminum sheet, 1 mm thick, thru the grind, using: aluminum specific heat, 0.902 j/ degrees celsius volume of plate, 1439.2 cm^3 aluminum density, 2.7 grams/cm^3 temperature, 120 degrees celsius (abs in mind) taking 1000 w as reference power, the whole thing comes to about 420 seconds, 7 minutes. i'm still rubbing my eyes, am i doing something wrong or am i living the dream? if the heated aluminum plate goes to work so fast, in real world i can expect 20-30 minutes, adding an 8 mm tempered glass on top. to prop it up some more, i'm thinking to boosting the power to 1500 or 2000 w, but the catch is i'm not sure how much pain could my house wires take, and i don't plan on finding out the hard way. how far up should i go with this power before i get an indoor firecracker festival on my hands? thank you so much. Val