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So I placing the resistors in my second hot end last night and I was wondering if the I could use the 40W heater cartridge instead... The resistors just seem so Jerry rigged and the fact that I could short it out scares the hell out of me.
Also do they produce enough heat? Do you need two per hot end??

a lot of us are using them already. you only need one.

Yes, you certainly can use the cartridge instead of the resistor.
You only need one and they do produce enough heat.
I think eventually the resistors will be a thing of the past, the
cartridges work that well and eliminate the possibilities of shorts.

Excellent. ..thanks for the info. Do you still need to use the rtv to hold it place?

Crap, wish I'd asked that question. I literally just purchased the screw in thermistor and could have picked up a heater cart at the same time!

The need for RTV depends on how snugly the Cartridge fits into the bore. If it is a slightly loose fit I would use a small
amount of RTV simply to prevent the Cartridge from moving. It is best to err on the side of caution and use a small
amount of RTV. Use the RTV on the ends, do not put RTV around the Cartridge in the heat chamber, if it is too loose
in the chamber a couple of wraps of aluminum foil would help tighten it.
They are making HotEnds now that have a set screw designed to hold the Cartridge in firmly.
Things, they are a changing.

cpunches wrote:Crap, wish I'd asked that question. I literally just purchased the screw in thermistor and could have picked up a heater cart at the same time!

I just got mine in as well as I ruined one of thermistors when i was using the marlin firmware and hit the home key and it pulled it right out... You will have to tap a m3 thread into the hot end. Its not bad because the hole is already there is the right size.

Eaglezsoar wrote:The need for RTV depends on how snugly the Cartridge fits into the bore. If it is a slightly loose fit I would use a small
amount of RTV simply to prevent the Cartridge from moving. It is best to err on the side of caution and use a small
amount of RTV. Use the RTV on the ends, do not put RTV around the Cartridge in the heat chamber, if it is too loose
in the chamber a couple of wraps of aluminum foil would help tighten it.
They are making HotEnds now that have a set screw designed to hold the Cartridge in firmly.
Things, they are a changing.

Thanks for the tip Eaglezsoar! I was scared of the aluminium foil because of the whole shorting issue again and ended up using Kapton Tape. I forget what size tape roll I have but it can't be much wider than an inch. I took about a six inch peice in length and sliced it down the middle and rolled each resistor up with only one half of the six inch . It fits snug as a bug in a rug and again no worries of it shorting out.

Also has any one tried to tap the hole that is in the center of the cartridge heat chamber and place our own set screw or is it to thin thread? Can't remember off hand?

You can not wrap the resistors in Kapton tape. The wrap has to conduct heat, Kapton does not.
The only practical wrap is aluminum foil. You just have to be careful and wrap the center of the resistor and
keep the foil away from the resistor leads. If you have yours wrapped in Kapton, get it off of there before
you connect the hot end. The whole principle is that the resistor generates heat and that heat gets conducted
to the body of the hot end. If you put an insulator around the resistor (which Kapton is) you stop the heat
conductance and burn out the resistor. Find yourself a Cartridge if possible, if it is loose in the hole use a small
amount of foil to help tighten it. DO NOT USE KAPTON! As far as drilling and tapping for set screws, that would
depend on the HotEnd, your skills and a number of factors. I would let the manufacturers do it and use foil if it
is needed, most cartridges fit snugly enough that they don't need anything to hold them in. Again I want to
re-emphasize do not place RTV, Kapton or any other insulator inside the heat chamber! Only use those to insulate
the wires or on the ENDS of the heater to help prevent it moving.

Wow had no clue and have done about 12 decent size prints...thanks for the heads up. Looks like i'll be getting the cartdriges after all.