A couple weeks ago I started noticing some black goo on some of my prints. Within a few days I found the cause, the resistor that provides the heat for my J-Head had gone critical and melted down.
I did a little reading on this and I have a few ideas on ways to improve on the design to avoid this in the future, but I’ve had such luck with the standard setup I ordered a replacement so I could get back to printing and then experiment with the old head on the side.
One thing I’m doing different with the replacement is using “muffler putty” instead of aluminum foil to ensure a tight fit between the resistor and the body of the nozzle, since failure at this interface can lead to premature resistor death and may have played a role in the failure of my last nozzle.
I wasn’t exactly sure what kind of putty to get, so I went with Blue Magic’s “QuickSteel” since it had the highest temperature limit of the options I had available (the others topped out a little too close to ABS temperatures for my taste).
I’m somewhat concerned about what it might take to remove a resistor secured in this fashion when it eventually fails, but I guess that’s what drills and Dremel’s are for right?