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So some time last year (or longer...I'm fuzzy on that), I picked up a gen-u-ine .25 nozzle J-Head from hot-ends.com. I finally had a chance to get it set up so I can put it to use printing instrument needles.

I took the opportunity to use that fancy new crimping tool with some of the crimp tubes I'd bought a couple of years ago when I was working on the TAZ hot end. As most of you know, you can't solder the heating resistors - the solder will evaporate over time and you'll get an intermittent or failed connection.

Here's what the J-Head's single heating resistor looks like crimped out: You cover those crimps with a little bit of Kapton and you're good to go!

Here's how the thermistor came out, same process. The wires are 24ga and that big thing in the top of the photo is a .7mm Mechanical Pencil. Next, the resistor and thermistor get taped in place with a single wrap of Kapton. The Kapton holds things in place until the silicone heat wrap is done. Unlike the SeeMeCNC hot end, the resistor the J-Head uses leaves little room for movement, so the RTV isn't required to protect it.

Next, the wrap: The silicone wrap helps insulate the heater block from the ambient air and also provides additional force to hold the thermistor in place. The silicone wrap should be itself wrapped with a one or two layers of Kapton. If it's not there, the silicone rap can split and fall off the hot end.

Now the 4 pin latching connector gets added: Finally, the whole thing gets installed into one of travelphotog's J-Head adapters: All that's missing is the push-fit connector at the top.

Note that for those using this J-Head, the thermistor is a Semitec 104GT-2 and you'll need to tweak your thermistor table selection accordingly.

g.

Does the silicone tape have the little green stripe down the middle of one side? Used to use tons of that stuff on canon plugs rewiring bomb racks.

Thanks Gene for another great article.

Thanks Gene, looks really good.

I end up with scraps of this http://www.mcmaster.com/#6172t11/=11ejp8m periodically and will slip this over the telfon sleeving and crimp as another protective layer and to bind the wires together.

Would you require a cooling fan for this type of hotend, like the stock seeme hotend would need a peek fan?

Holy1 wrote:Would you require a cooling fan for this type of hotend, like the stock seeme hotend would need a peek fan?

Pretty sure all hotends need a cooling fan.

You can sometimes get away without a peek fan on a JHead even with PLA, but I (would and do) run one anyway.
Jou don't need a lot of airflow, the bulk of the issue is convection, so your just trying to keep the air around the peek moving.

barry99705: It's actually a blue line, but yeah, it's the same stuff. I use the black version of it when wrapping the tails of the cannon plugs on my F-15 project.

Eaglezoar: Thanks!

ccavanaugh: is that similar to the sleeve material that's on the wiring that the heater cartridges use?

Holy1: The barrel on the J-Head is made of PEEK, so yes - you do need a fan on it. It doesn't have to move much air though, just as Polygonhell mentions.

g.

ccavanaugh: is that similar to the sleeve material that's on the wiring that the heater cartridges use?

Yes... I've seen it used as sleeving for motor brush leads to prevent shorts