First layer printing blobs and strings after faulty print  

First layer printing blobs and strings after faulty print

Hi all -

I work in a hospital research group and we just recently got an i3 mk3 and are looking to 3D print a full size skull model. We managed to print one (~60 hrs of print time), but when we went to print it again, we came back the next morning with a mess of filament everywhere (see attached). We also noticed that the nozzle fan component had broken off - which we managed to reprint a OK version of to continue using the printer. Not sure if a collision happened or what.

We went to do some other prints (and first layer calibrations) but the prints are very stringy and bloby (see attached image).
Now - we have re-calibrated the printer completely. The first layer sticks quite well, but the nozzle gets caught up in the blobs and stringy bits and we can never get past the second layer of a more advanced print. I have decreased the extruder multiplier to 0.9 and have taken off the nozzle and cleaned it out. Calibration of first layer sticks, except on some of the corners (as seen in the attached image). I have learned that a 99% isopropyl alcohol is better than 70%, which we'll try out.

Keen on any other suggestions/experiences/solutions that folks can offer. Thanks in advance.