Using 3 pieces of acrylic, 1 6inch by 6 inch board and 25 to 30 220ohm resistors i made this heater plate. you can make it too! - i soldered one end of the resistors to the copper board, applied a thin layer of tape to the area across that was not soldered, and then soldered the other end to a wire . the red wire was positive, the copper plate was negative, i then soldered the copper board with a black wire, and then taped several times over the copper side with the resistors several times to allow heat to stay in. using the resistor values is ok, a method that uses 330ohms is used to keep telescopes from fogging at night. the idea is to provide enough energy in heat that can be dissipated safely. the soldered end of the resistor transfers heat to the copper board. the copper acts as a heat spreader, and the pcb acts as a good stick layer for thermal plastic. I also have a video here: http://www.youtube.com/watch?v=pDEkp3ym1TEyou need a 6 inch by 6 inch copper board. 4 oz of alumilite poly urethane (high temp cure plastic025-30 220ohm resisters (not any lower that this value, and max voltage 14volts!)a cnc machine to cut out parts. the file is what i used to cut thru 3 .1 inch layers of acrylic stacked on top of each other and mounted. the top acrylic sheet will have a 6inch by 6 inch square. use grinder and re size circuit board to fit into this square. add in resistors evenly spaces, although since copper spreads heat it should not need to be exact. once device is wired, then pour urethane to keep resistors safe and to keep heat in. also the part that faces out is the pcb side. the copper side is is inside and coated with urethane