Extrusion problems.. [x-post /r/3dprinting same username]

255? when I print at 255 with an e3d v6, the plastic is so amorphous that it's almost like a liquid; I can only use temps like this at really high speeds. I would back down to 235-245 for ABS, and try a different brand. I prefer Octave.

obviously i recommend upgrading to the e3d, because even if it clogs (it won't with ABS) it's a no brainier to fix (280c for five minutes toasts all clogs).

if your temperatures are that inaccurate then something is very wrong. it may not even be a clog -- how do we know it's reaching a reasonable temperature? when left to sit for a while, do the temperature readings reflect the ambient temperature of wherever your printer is?

it shouldn't matter if you use an e3d or not. if the thermistor goes inside the heater block e3d temperatures should be comparable. if it's on the outside held with Kapton tape that's a different story.

First, let me just clarify something: are you able to push the plastic through the hotend by hand, or does the filament buckle when you try to keep pushing it? If all is well you should be able to push plastic through and see it come out of the nozzle. I ask because other possibilities are your extruder stepper motor is malfunctioning (apparently the wire connection can be problematic for some Press users)/not getting enough voltage. Obviously, do this with the extruder apart so there's no tension on the filament; you can leave the motor gear on if you have room. If you CAN push it through, ignore the next paragraph.

I'm also wondering if your thermistor is poorly seated. Does moving the thermistor wires back and forth change the temperature at all? You might try re-seating it in the heater block altogether just to make sure it's in there securely. Then try again and see if anything changes.

It's possible the thermistor is part of the problem, however, if you can push filament through by hand and see plastic come out the other end, the hotend is not clogged. Partially clogged, maybe, but the motor should be able to drive through it.

Try this. Take the extruder apart, heat the hotend and request 100mm of filament extruded. Grab the gear with your hands and try to stop it from rotating. Does it slip or stall the motor? If it does, you need to increase VREF; have a search, I don't know exactly where the trimpots are on the Press but it's been discussed many times. If you can't stall/slip the gear, but you are able to push plastic through by hand, you may have a tensioning problem with your extruder (it's not pressing the filament against the gear hard enough so it's slipping).

Pulled apart the hotend, soaking the cold end connector tube thing and the nozzle in acetone.