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Heater Replacement

Posted by ScottieD369 
Heater Replacement
February 13, 2016 02:18PM
Hi there I had some bad wiring on my heater so I was able to get a replacement sent to me. I never needed until now to actually replace it. Because it would still work by a little jiggle. So since I was scared of failed prints by loosing heater connection and really couldn't recover anymore I went ahead and disassembled the extruder. So then of course I have to cut the Kapton tape and insolation so I could get at the set screws for removing the heater. Then while everything is apart also make sure everything is clean, yank out any plastic. Then putting everything back together I have no Kapton tape for the heater block or insolation to replace. Now I ordered a roll of tape but I am unsure what was used as an insulator that can stand that heat? Anyways I was able to put everything back together and get it working again.

But here lays the problem. I did make sure everything was nice and snug tight the top and bottom set screws and nozzle. BUT there are bubbles forming and burnt plastic. Now I tighten everything down even more but it's alot better. But I'm at the point now that if I tried to tighten down more it would all break. So somebody suggested to me to use Copper grease on the threaded rod where the nuts were. Now I was thinking WHY? Copper? Why not Lithium grease? Then asking another person and we both agreed to try the Red High Temp Grease and that hopefully should solve this issue? So I am wondering any thoughts as far as anybody else experiences dealing with this, what you used to fix? Please let me know in the Comments Below.

Edited 1 time(s). Last edit at 02/14/2016 12:28AM by ScottieD369.
Re: Heater Replacement
February 13, 2016 02:21PM
PS No it is hard to actually take a picture of this on the printer without disassemble. So I can't show you only explain to you right now.
Re: Heater Replacement
February 13, 2016 03:27PM
Or I have a theory that it's just "breaking in" and that seals itself and the seapage should stop?
Re: Heater Replacement
February 13, 2016 11:42PM
When I rebuilt mine I threw away the Kapton tape never to use again removed the nozzle and heated out all plastic pulled out the thermistor and heater cartridge, removed the block and then the barrel and cleaned the teflon tube out. Reassembly on the MK8 required threading barrel up into extruder till it stops threading a nut up till it stops and snugging up. Put the nozzle into the block threaded onto the barrel till it stopped (block may be at a bad angle) so Now back off the nozzle about one turn and thread the block up 1/4- 1/2 turn to align it square then tighten nozzle so that it makes good contact with barrel inside the block no gap and tighten nozzle while holding the block if the nozzle bottoms out and block is loose unthread nozzle one turn and spin the block up one turn till square and retighten nozzle . You want no gap between the nozzle and the barrel or plastic may extrude out of the block. In my case I used the RED RTV High Temperature Silicone (Permatex) on the threads of the barrel before I threaded the aluminum block onto it, no more ooze. Then I coated the thermistor in Red and put it into tiny hole in the block making sure it was firmly in place and let dry an hour or more. Then you get white heat sink grease used for transistors (Radio Shaft etc.) and coat the heater tube/cartridge slide it in and snug up the set screw, fasten heater and thermistor wires to bottom of carriage so they don't hang down loose or drag on parts as the X axis carriage moves and try it out. No More Kapton. Now my temperature stays where I set it before it would drop 20 degrees. The best way I found to clean nozzle was to heat it up with butane torch till orange and smoke free spin a toothpick or Qtip inside to get out residual carbon particles or compressed air and if by chance the nozzle did some dragging on bed or parts hand thread appropriate hair size, hard to see, easily lost or broke fractional metric drill bit of 0.2 + mm into the tip. Some use acetone to soak them in, others get high off it. ABS hates it PLA ignores it so I simply cremate it

Re: Heater Replacement
February 14, 2016 12:22AM
Thanks Roger for your sharing experience. See I think that the Red Grease is a good idea and you backed me up on it. So I am going to try your method too and making sure that the threaded rod and nozzle meet up. I think they are just too low? Anyways I ran a few prints and it's not that bad but it is seeping very small cause every once awhile I can smell it. So it's worth looking into for fixing but can hold off no immediate damage.
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