Heated Polyester Moulds

Im looking for a low temp heating solution for a polyester / chopped strand mould, embedded within the mould itself. I do lots of work normally with high temp heated moulds but am trying to go back to basics and super low cost with this one. Only need 45 degrees C approx. Any ideas
Underfloor heating mats perhaps - other flexible membranes that could be embedded
Cartridge heaters maybe but trying to get decent uniformity
Silicone heater mats are a back-up but would prefer them to be embedded.

resistance wire, or carbon fabric works well. I recently designed heated removable mould flanges using carbon heating fabric, 48V DC, and thermostats(http://www.easyflip.co.uk/CPC_Digital_Catalogue/?page=3408) imbedded in to the laminate to control temp between 80 and 65C. If you need tighter control you will need to imbed thermocouple or NTC sensors in the laminate and have a PID control with SSR or regular relay.