RepStrap: building an extruder...

I started building my extruder in the last few days. I am still waiting on a stepper motor driver board, so there is no hurry to get this working. However, I have made quite some progress.

Here is a picture of my heater.



Here is picture of my pinch wheel driven by a Nema 23 stepper motor. Overkill? Maybe.



A pinch wheel extruder is still very cutting edge for RepRap and so the details of how to correctly build one are still being talked about. When I read the builder's blog a few weeks ago Adrian was suggesting knurling the stepper motor drive shaft. I purchased a knurling tool for a lathe from a tool shop for $8 and rigged up a vice, twisting the drive shaft in the vice to complete the knurl. It appears to have worked pretty well. I guess we will just have to see...

The red substance on the above heater is my solution to a problem the RepRap team has been trying to solve for quite some time. How do you hold a barrel, some nichrome heating wire, and a thermistor together at temperatures above 190 degrees Celsius? My solution is some Red High Temp SuperFlex LOCTITE silicone based sealant. How long will it hold up before it starts decomposing like other substances the RepRap team has tried? Again, we will just have to see...