Clog clearing and extruder disassembly: help!

[jsc]

I had a bad clog, and trying to clear it with an allen wrench through the feed hole didn't work. I decided to try a full tear down. Now I'm halfway through, and stuck. I have a few questions.

On the left, I an at the point where you use a pair of M6 nuts to unscrew the nozzle. Only, I can't seem to get that to work. Whenever I turn the nozzle, the entire assembly turns as a whole, and the nuts just start unscrewing off the end of the barrel together. What's the trick?

On the right, you can see where I managed to do something weird to the PEEK insulation, and now the white bit is sticking out of the black bit, and the two pins have come free. I can tell this is not what it's supposed to look like because it can't snap into the filament guide in this state. How do I get that part all back together?

[jimc]

jin the pins in the peek are not supposed to come out. no big deal though really. the white liner will push back and stick the pins back in. the 2 nut may need to be twisted together on themselves a little tighter if they are spinning. you can also heat the hotend up and try it. there may be plastic inside still that is bonding you nozzle to the tube. put a wrench on the heater block and another on the nozzle and unscrew them from each other. you just want to make sure that the block and nozzle are locked tight together like the 2 nuts are on the other end.

[jsc]

I managed to get the nozzle off. With Josh's help on IRC, I got the PTFE insert out of the PEEK barrel, but couldn't figure out why it wouldn't seat properly until Josh pointed out that the dirty bit up top wasn't supposed to be there.

ptfe-insert.jpg (77.17 KiB) Viewed 17873 times

plug-removed.jpg (71.3 KiB) Viewed 17873 times

[jsc]

I am not able to pass filament through the brass barrel. I should be able to easily since it is 2mm ID. How do I clear out any residue inside?

[jimc]

you print alot in pla so you would need to soak it in methylene chloride / paint stripper or run a 2mm drill bit through the tube. home depot has a thinned out sprayable paint stripper that will work.

[jsc]

Thanks, Jim. I know you've said these things before, but I always ignored those threads with the understanding that it would never happen to me. Do you know the brand name of the stripper you mentioned?

Also, this page was useful: http://makergear.wikidot.com/m2-hotend-assembly

[jimc]

Jin its sprayable stripper from kleen strip. I think they have it in quarts and gallons. Just soak the tube for a couple hours then a pipe cleaner or something to run through the barrel will clean it right out. Soak the nozzle as well. I have never pulled the ptfe out of the peek like that so im not sure if what you have there is normal.

[MarkG]

Jin its sprayable stripper from kleen strip. I think they have it in quarts and gallons. Just soak the tube for a couple hours then a pipe cleaner or something to run through the barrel will clean it right out. Soak the nozzle as well. I have never pulled the ptfe out of the peek like that so im not sure if what you have there is normal.

I also used another piece of advice that worked much better that the paint stripper: heat it with a torch (or even a bic lighter) then push the plastic out with a suitable allen wrench or (in my case) a 2mm harbor freight drill #80.

When mine was totally full, it took me 3 days to push it out with the chemicals, and 20 seconds with the torch. I'm sometimes impatient.

Frankly, I'm getting much better luck using Josh's advice for cleaning the tip, but I do it more often, before it gets completely blocked. Josh posted a procedure that allows for NOT disassembling the hot end.
Mark

[jsc]

I tried the heater, but it looks like I've got filament caked onto the wall, and it's difficult to "push" on it with an allen wrench. I have a 2mm drill bit coming on Monday, but in the meantime I've got some "Handi Strip" at Lowes (http://www.lowes.com/pd_206487-34228-CR ... Id=3024042), which has methylene chloride in the ingredients list and comes as a liquid. Trying that now.

[jimc]

Thats good jin. As mark said though and i forgot to mention that if the tube is caked solid it can take a long time to soften the plastic. I usually just take a small drill bit and drill through the plastic to take the bulk of the material out so the stripper can go through the middle of the tube and work on the plastic faster. If you do that then its usually a couple few hours of soaking.