Thermoplast Extruder Variations

Design:

• Direct Drive
• Geared
• Grub Screw in lower end of PTFE Insulator to help hold the brass barrel when using higher temperatures
• Drive screw can be smooth for most of it's length. It reportedly only needs about 7 complete threads to dig in, the rest just add friction.

Materials:

• Barrel:
  • Machined out of a brass bolt.
  • Aluminum has been used successfully.
  • Combination of stiff copper tubing and copper plate brazed together was used by Forrest Higgs.
• Orifice:
  • Mechanical pencil tip was reported to have heating problems.
• Barrel dielectric material:
  • Furnace cement is now the officially recommended material.
  • Both High-Temp JB weld and bar-b-que paint degrade after a hundred hours or so.
• Pump:
• Insulator:
  • Originally designed to be made from PTFE (Teflon
  • PEEK (w/o fiberglass reinforcement is reported to work)
  • Concrete has been reported not to work (tried by vik, who still hasn't supplied details)
  • Drywall mud (shrinks and cracks horribly, tried by John Gilmore)