55 hours of orinting in PLA - Hot end problem

[duvdev]

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]

[geneb]

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.

[gchristopher]

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

[geneb]

No kidding!

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

g.