Welcome to the SeeMeCNC Community

I'm assembling a hotends.com J Head and trying to take pictures of how I did it. I haven't written the steps yet (or finished the build), but here's the Imgur album of what I've done so far:

http://imgur.com/a/xjlyd

My main departure from the "standard" assembly steps is that I've wrapped the head in Kapton tape to try and cut down on radiant heat a little (3 layers so far). Only cutting out one hole for the resistor and just poking a hole on the other side for the resistor lead made for a nice clean heater install too (no blobs of extra silicone, and I'm fairly confident that the hydraulic action of pushing the resistor into the silicone pumped out any air bubbles that might have otherwise been present).

What is the J head's black piece make out of?

jake wrote:What is the J head's black piece make out of?

PEEK the same as pretty much every recent Hotend prior to the recent flood of all metal designs.
There are a few older/poorer hotend designs that use PTFE structurally, but it tends to creep making failure inevitable.

I have owned and still currently own a few genuine heads and e3d's and can truly say that a real head (only the ones from hot ends.com btw are the real deal) is still by far the best performing and most forgiving hotend for PLA exclusive use compared with any other hotend on the market.

I do honestly believe I own every single hotend commercially available when I say this as well. This includes every version of the e3d also.

The e3d is currently the best hotend IMO for everything else out there other than PLA. (And I do believe I have nearly every material filament wise available for printing in the 1.75mm range of filaments on the market today)