I just changed from an older J-Head 0.5mm hot-end to a new Mk 8 0.3 mm hot-end.

My old prints using the 0.5 mm nozzle were OK (none of the problems described below), but detail for small parts was not what I was looking for, so I purchased the 0.3 mm hot end. Very nice. Simple Install.

Now I’m having a few problems, which I believe are settings and not the head itself. I’m using the same filament – PLA.

I’m now seeing Three problems, probably related - pictures below: (1) I’m now getting some very fine hairs as the print is being printed. (2) The first part of my initial layer (actually a skirt to get material flowing) tends to “skip”, putting down material/gap/material/gap, etc. (3) When the print is finished, the nozzle continues to extrude material. I’ve even manually retracted 2-3 mm and it still extrudes material for a while (a couple of inches worth of extrusion of regular diameter - 0.3mm approx. – not just a wisp).

I’m using Slicer with Repetier-Host. I have the filament size correct (same as before, 1.75), nozzle size at 0.3mm, first layer height at 0.25mm, subsequent layers at 0.2mm, printing at 205C (what I used with my 0.5mm nozzle), bed temp at 45C. I think I’ve correctly readjusted the bed level for the new head (piece of paper between the head and glass will slide in with a little resistance. I have retraction set at 3mm.

Any ideas what setting(s) I might change to get this to print well? Thanks. Pictures:

This shows the hairs (this happens to be a better print). The strand going off to the top-right is what happens after the print is finished and I manually have the extruder move to the right limit, raise up 10 mm or so and retract about 3 mm. Then it keeps extruding off to the side for a bit.