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Hot end leaking brownish-blackish plastic onto print

Posted: Thu Feb 04, 2016 7:28 pm
by LiccaDollhouse
A couple of weeks ago, I've had to replace my hot end due to a thermistor "accident".

Now, this hot end appears to leak black molten plastic onto my prints when I print with PLA. It does not happen with ABS (but only like 5% of my printing is with ABS, it may not be a significant sample).

My printer is completely stock on the extruder and hot-end side. (The only thing that isn't stock with my printer is the arm that holds the filament up.)

I print PLA at 205-220 degrees C, depending on the color of the filament, and I print ABS at 225-235 degrees C.

Any suggestions on how to mitigate the problem that doesn't require me to buy ANOTHER hot end?

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Thu Feb 04, 2016 9:17 pm
by Eric
Was the ABS you used before black?

I'm thinking you need to do a purge at ABS temperatures to get any remaining ABS out of the hot end, then bring it back down to your PLA temp for actual printing.

If that doesn't do it, removing the nozzle for a look-see would be the next step.

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Thu Feb 04, 2016 9:27 pm
by LiccaDollhouse
Nope, the ABS was white, and I purge at 230C with PLA to get it out of the nozzle.

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Fri Feb 05, 2016 12:17 am
by Xenocrates
Maybe tighten the nozzle a bit while it's hot (ABS temps, ish), to make sure it locks tight and doesn't have any slop at PLA temps?

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Fri Feb 05, 2016 12:34 am
by LiccaDollhouse
Okay, I'm tightening it and see if that helps. The brownish goop usually ends up a couple of hours into a print, so I should know pretty soon if that helps.

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Fri Feb 05, 2016 7:56 am
by geneb
If the nozzle is leaking, it will be VERY obvious. You'll see plastic on the flats of the "nut" at the top of the nozzle.

g.

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Fri Feb 05, 2016 1:08 pm
by Eaglezsoar
Did you reuse the nozzle from the old hotend that was bad, or did you use a new nozzle?

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Fri Feb 05, 2016 10:46 pm
by LiccaDollhouse
No, I used a new nozzle (namely, the one that came with the new hotend).

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Wed Feb 17, 2016 11:17 pm
by LiccaDollhouse
I would like to give an update. After tightening the nozzle slightly, I no longer have this issue.

I guess I should be a bit more brave in tightening things. :D

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Thu Feb 18, 2016 3:50 pm
by Eaglezsoar
LiccaDollhouse wrote:I would like to give an update. After tightening the nozzle slightly, I no longer have this issue.

I guess I should be a bit more brave in tightening things. :D
Thanks for letting us know how you fixed it, it is a good one to remember.

Re: Hot end leaking brownish-blackish plastic onto print

Posted: Sat Feb 20, 2016 5:44 pm
by LiccaDollhouse
Eaglezsoar wrote:
LiccaDollhouse wrote:I would like to give an update. After tightening the nozzle slightly, I no longer have this issue.

I guess I should be a bit more brave in tightening things. :D
Thanks for letting us know how you fixed it, it is a good one to remember.
I think it would be helpful if the instructions can list a torque value, so we can use a torque wrench to get the nozzle the proper tightness.