Leaking hot end on MK3
I have recently started having a problem with a leaking hot end. At first, I thought it was because the nozzle was not tight, so I made sure it was, and the problem continued. That's when I realized it was leaking from the top of the hot end.
A little bit more background: the problem started happening in December after having good prints since July. I had been printing a lot of black hatchbox and esun PETG when the problem started and started getting worse. The way it first manifested is that eventually a blob would form on the heat block and catch the print. I ordered some replacement nozzles from E3D, and put in a replacement 4mm nozzle. That seemed to help for a while, but the leaks are getting worse now.
I bought the extruder upgrade kit from Prusa and figured I'd clean off and tighten the block while I was taking it apart. I've started taking it apart, but I realized I have no idea how to proceed from here. I have posted some pictures here:
I contacted Prusa support chat and got the response:
OK, so we dont have any advice - it mst be properly tihtened together and fitting well. There is no manual or etc.
I watched this video, which would have been helpful when assembling the printer, but doesn't seem to have enough info to get me out of my current jam:
My initial thoughts are:
Power up the printer, heat up the hot end, and clean things off with a brass brush.
try to tighten the block and the heat sink, and make sure the nozzle is tight
put it back together and hope for the best
Questions I have:
A) What caused this in the first place? Is it the problem from the youtube video? How can I avoid it happening again.
B) Is it safe to heat up the hot end without the fan on the heat sink? Would it be better to use a heat gun?
C) How can I / should I try to remove the heater and thermistor from the block and try to clean it?
Re: Leaking hot end on MK3
Did you confirm the nozzle is NOT bottomed out in the heater block? In your photo, the nozzle looks like it is tightened against the heat block and not against the heat break. There should be a gap between the nozzle HEX and the aluminum heater block as shown in the drawing.
Also, the nozzle must be tightened while the hot end is at 280c.
Re: Leaking hot end on MK3
I have also run into this problem. I don't really have a solution yet but it did look like my nozzle was loose. However I did find a very good article on assembling the E3DV6 hot end.
For the Prusa you don't need the whole article but it is useful information to keep on hand.
Also for the Prusa printer make sure when you put the heater and temperature sensor in from the correct side or it will be wrong when you start to reassemble it. I believe the first pictures show it opposite from the Pruse. It will go in either way so just be careful.
Good luck