The hot end of the extruder is a spiral of nichrome wire wrapped around a piece of brass tube, smothered in fire cement and shrouded in a piece of copper tube.Well, it would have been fire cement except Buzz had a small amount of high-temperature epoxy available instead. Which was nice because it cures by itself in an hour instead of requiring a couple of days or a trip to an oven.
What wasn't so nice was what happened when I fired up the heating element. Fire cement would have happily taken the abuse, but instead the epoxy emitted incredibly foul smelling smoke. At this point I don't actually have the temperature control loop in place, so I probably exceeded the epoxy's max temp (260C, which isn't much above our desired working temp). The rest of the afternoon was pretty miserable, waiting for the smell to dissipate. People walking past the windows started coughing, including Paul - and he was smoking at the time! Even after the smell had abated from the room, I still had it clinging to the skin on my hands and suffered whenever they got too close to my nose.The hot end is still in working order, thankfully; but I'm leaving it till the very end of the build before doing anything more with it...
3 comments:
That was a very bad idea... epoxy no good for that kind of use.
Perhaps. But Buzz is using it in his extruder satisfactorily, so I hope I won't see any more problems if I don't overheat it again.
Nothing is stopping me pulling the hot end apart and rebuilding it if it is absolutely necessary.
I'd say get some of the cement.
Epoxy and high heat = not good. For ABS that barrel is going to get very hot.
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