New i3V owner: A few beginner questions

[printbus]

Welcome to the i3v club!

I've been using 225 degrees without issue. I've read on other forums that the uncalibrated thermistors tend to read high, so setting for a temperature of 225 might actually turn out to be lower in terms of a real temperature. Just a thought. Some people have described disabling the stepper motors, and then manually rotating the large gear on the extruder to get a feel for how the filament is extruding at different temperatures as a way to figure out the optimum temp setting. I tried that, but I found it hard to notice much difference.

On your first layer, it could also be that you have too much space between the nozzle tip and the glass. I adjust mine so that a piece of paper is fairly snug between the two. If you haven't already, by all means calibrate the feed rate of your extruder. Mine was low by about 5%. That'd be another reason for not enough coverage on the first layers. I've been tweaking the Slic3r settings recently, but used the MakerFarm configurations for a number of things successfully. Google on extruder calibration for info - look for calibration videos my Zennmaster. Finally, if you try to move around the cold extruder tip manually, does it feel loose? Mine did, and I went back through the extruder assembly to eliminate mechanical play wherever I found any. See Post #17 in the Printbus build log for details on what it took to eliminate that play. I felt that having a solidly mounted extruder tip was important to especially the first layer.

On the extruder, check to make sure the two bolts on the upper rail wheels don't rub against the large gear. Mine were rubbing. I didn't work through whether the rotation direction fits, but maybe that could be part of the reason why the gear tightens up on you.

Swap out the filament by cutting off the filament with a length extending from the top. Using pronterface, turn on the nozzle heater and wait for it to get to temperature. Then using the "reverse" button on Pronterface, back the filament stub out of the extruder while gently pulling on it. I usually set Pronterface up for a long value like 50mm, and then gently pull on the stub while also releasing the spring mechanism. I don't like using the 0.1mm steps available on the LCD to control the extruder. I cut my filament with an anvil cutter that makes a very clean cut, and cut at an angle to make it easier to feed the new filament into the extruder.

Following a hint I found elsewhere, I used a dab of automotive muffler cement to affix the thermistor to the hot end. That seems to have worked pretty well.