Thermoplast Extruder Variations

Design

• Direct Drive -Does not use flexible steel cable)
• Geared - Goes slower, but provide more control on the amount extruded)
• 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.

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)