Hello, can anyone help me finding out what is dark gold (brown) substance around nozzle?
It seems that sometimes it comes down and makes print look dirty, and it doesn’t smell good (like normal PLA) - just like burning oil.
I was printing 200C PLA and now I am doing tests for 185C.
Prob burned plastic.
Check that your printhead is not leaking molten plastic above the hot end. Happened to me before with J-head when PTFE tube inside cracked…
That’s what you get for buying a knockoff J-head and not the real thing, that’s exactly what.
I would guess that your hot end is leaking plastic and burning it on the sides. What kind of extruder do you have on this machine?
Its kapton tape
The print head has Kapton tape wrapped around it- I see the brown substance on the print - it could be from the Kapton, but it could also just be carbonized plastic that curls up and gets caught on the nozzle for too long.
@Michael_Moskie it is direct drive Mk7 gear extruder, why do you ask? Does it matter what extruder it uses?
@ThantiK you are right bought it off ebay, it is 0.3mm nozzle, already printed maybe 1kg of plastic through it.
Is it possible that it is some glue coming off from kapton tape?
Thank you all, seems like I need to add disassemble it at some point clean up and seal it.
Ive never had a problem like that with the kapton tape. I would bet it is like +Phil Wheat says, carbonized plastic from another print or just overheated plastic that hang around the nozzle and felt over your print.
Fernando - I haven’t had problems with Kapton doing that, but I can’t say I’ve had it that close to the print head (unless you count it being on the print bed itself.) So I didn’t want to rule it out completely, but it isn’t my top bet either.
The picture shows burnt PLA just below the heater block. Something I is leaking. I could be as simple as the nozzle being a 1/8 turn loose or needing PTFE (plumbers tape) where it’s threaded on.
@Mateusz_Perlak the extruder isn’t relevant to your issue, you just have pretty good print quality outside of the leakage and I’d like to try to replicate that 
Thank you all,
I think it is burned PLA. I lowered extrude temperature to 185C (from 200C) and seems to help.
My suspicion goes to lose connector on termistor, which may be lose up for a second or two making extra heat going in to heaterblock.
I noticed this temp variations when burn PLA smell occurred
https://docs.google.com/file/d/0B3V5LBe0yZ7ORmM3TU9oRE9zMlE/edit
probably some lose cable or termistor contact issue