We’ve come up with a way to easily build a cheap “hot box” to any size you want.  Our design will create convection currents and maintains constant temperatures, resulting in even heating of materials which is exactly what you need.  The foam board and other materials needed to build the hot box can be found at Home Depot or other DIY stores.

Materials And Tools
2” (5 cm) Foil Insulation Board
Heater 
1” (2.5 cm) Drywall Screws
Glass Thermometer
Duct Tape
Table Saw & Jig Saw
Drill With 1” Hole Saw, Screwdriver Bit, and ¼” Drill Bit