Blocked J-head - any tricks for clearing it?

I have been printing 24 hours a day for a while now and for the last week have had extruder malfunction after malfunction. At first I thought it was the hobbed bolt getting old and losing it's edge so I changed that, also changed the entire extruder, new gears and still printing problems. Finally diagnosed it as a blocked nozzle. I print with PLA so to clear it I ramped up the temperature to 230 using the ABS setting and this worked once but after that became blocked solid. I have taken it all apart and drilled out all the various parts except for the actual nozzle. Today I bought a 0.4mm drill bit so I will have a go with that tonight or tomorrow to see if I can resurrect it that way.
PLA doesn't dissolve with acetone so other than drilling it out I have run out of ideas.

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Richmond, New Zealand
Thingiverse ~ YouTube

blowtorch

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- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]

Blow torch and needles. Just burn it and take the bits of burned plastic out with needles from the inner side (the one with the threads), after you have taken all, use the bit to clean the small orifice, but use your fingers (or pliers), dont use a drill!. Then, lots of water, and some fabric to clean the inside, just like when you clean a gun barrel.


thanks how i fixed mine!

Unscrew the metal end, heat it up on a gas hob, melt out most of the plastic. Then while hot, stick some filament in and pull it out to remove some gunk. Repeat with clean bits of filament until working. Printing at 230 is far too hot for PLA and it will crystallise solid causing worse blocking.

yeah blow torch untill a nice silly hot then turn up side down to get it out.

iv heard people say throw in some water to make the plastic cool quickly but i wouldnt do it .

whatever you do when you reassemble your j-head do not put much presure when tighnting up to the peek or this will happen http://t.co/xnPuy95G or in my case happen twice

Yes I think I made it worse, the charred lumps finished it off.
Thanks for all the tips, I have a couple of these now so have some to experiment with.

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Richmond, New Zealand
Thingiverse ~ YouTube

nic0laz Wrote:
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> dont use a drill!

LOL wish I read this 5 days ago!!
... new one on order!!

How are you holding the hotend while heating it up?
Just a pair of pliers? (pics?)

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Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

Oh,
At what temp does PLA start to crytalize?
(I have 190c for first layer, and 185c for the rest)
(my IR thermometer wont read off the brass for verification)

The nozzle has plugged twice with these temps...(fairly quickly - 1/2 hour)

I've got a HOTENDZ with a 0.5 nozzle, and some black PLA from the MIXSHOP.

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--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold