After last weekend's failed print I ordered some blue tape, but in the meanwhile (it's been four days, and it's still not here. FTW, Trijexx?) I happened to poke at the bed, and it turned out the corner that the print head starts in was loose. Now I should recalibrate, just to be sure. And since the backpressure was high enough that no filament got pulled for a while, check for stripping.
But first, clean. Atom. Clean. Atomic. Clean... I'm coming to the conclusion that indeed this hotend is also pretty crappy quality. Here's what it produces when I press filament through:
Very uneven. And the atomics are black and dirty. I admit defeat, and now need to find a quality hot-end for a Wade's Extruder on a Mendel90. It would appear my current hotend is a J-Head Mk II. RepRapSource has Mk V's available, but I'm not sure the shorter length is a good thing given the fan shroud. On the other hand, they look pre-glued, which is good, as gluing was a pain. Not sure if e3d or hexagon are compatible with my (2013) Wade's while being not much shorter than 71.5mm. More research is needed.