Thermoplastic fabricating totally revolves around how you heat it up. Fortunately, there are lots of ways to heat thermoplastic, even at home:

heat sources

• soldering iron (for plastic welding)
• kitchen oven
• kitchen stove

heat moderators

• a double-boiler with oil in the bottom
• one or more cast iron skillets (stacked)
• anything on this list that has a higher thermal conductivity than water
  • graphite (highly conductive, 1lb costs ~$25)
  • concrete (varies a lot.... low-density concrete is lower than water... the more stone concrete has in it, the higher it is)
  • red brick
  • any stone, especially stones that are more dense
    • "paving stone", available in the 'outdoor' section of Lowes/Home Depot is pretty cheap
  • Pyrex glass