I am building a custom personal vaporizer and the MOSFET(s) I am planning on using are for flat mounting to a pcb. I want to directly solder the drain tab to a thick piece of copper and the source and gate to a pcb that is glued to the piece of copper. Because the copper is going to be a plate it will need to be heated either in an oven or on a hot plate to be soldered do the adhesive that holds the board to the plate must be able to withstand 600 degrees or more for at least the amount of time it takes for the solder paste to set. I want it to be soldered to the copper as a heat sink. If you have any ideas i would like to hear them.