Mendel90 Hot End 30mm Fan Duct

I found that I needed extra cooling on my J-Head mk4 hot end, so I designed this duct to add a 30mm fan to the Mendel90. This part fits inside Wingmaster's square fan duct (http://www.thingiverse.com/thing:657540) and tucks neatly under the X-carriage. Simply glue in place and add a fan with four #2 screws.

I've also added a version with two fans, for extra cooling power, but I haven't tried it myself as one seems to be enough. It may interfere with homing in the x-direction - if you try it, let me know.