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Hello

So I have a print job of 55 hours - Orange PLA stock hot end 0.5mm
After about 12 hours or so a black gooey stuff is coming out from around the nozzle and the top of it.

on about 63% of printing after wiping that stuff the hot end jammed and the print failed.

PLA is all over the place.
[img]http://i.imgur.com/1EVHROA.jpg?1[/img]
[img]http://i.imgur.com/cy58Ubk.jpg?1[/img]
[img]http://i.imgur.com/kLQEq0g.jpg?1[/img]

I bet you forgot to tighten the nozzle down when you built the hot end.

You also haven't insulated the solder connections for the heating resistors.

g.

Ouch, regardless of the cause, that's a painful one!

No kidding!

(I should also point out that soldered heating resistor joints will eventually fail. This is why crimp connectors are used.)

g.