This is the power resistor heater block described by nophead on http://hydraraptor.blogspot.com/2009/01/yet-another-quick-heater-hack.html (nophead, if you want to make a thing for this, I'll take this one down and post my pics as a copy, or I can just change the license to one of your choosing) made from the kit available from http://www.makergear.com/products/ceramic-heater-core (choose "Power resistor heater kit"). The power resistor acts as a heating element to heat an aluminum block around the heater barrel, replacing the nichrome in other hot end designs. It's installed in my oversized Mini Mendel Huxley (which has BARELY enough space in the bottom of the X carriage. Hopefully the radiating heat won't screw up the carriage, but I plan to make a new one when I get it printing anyway.Thingiverse is flipping some of my pictures upside-down for some reason, I'll try uploading them again later.You need a block of aluminum at least 19x19x8mm (mine is about 20x20x13mm). Using a drill press if you have one (I don't), drill a 5mm hole on one side for the heater barrel through any dimension (I would have tried making it through the longer dimension, but my barrel was too short) and tap it with a 6mm, 1mm pitch tap. Drill another hole through the long dimension the size of your power resistor (6.5mm was too small for mine, and 7mm needed some aluminum foil padding). Drill a third hole just large enough and deep enough to embed your thermistor. Being sure not to short your leads (the makergear kit comes with some thin PTFE tubing for insulation, and I also used polyimide tape to seal it up), wire the resistor and thermistor to your extruder controller.