Skipping partial perimeter and extra mid-air infills for funzies.

I printed the two objects I attached and if you look, you'll notice various defects in the prints. Overall, I'd say the quality is pretty decent (nothing to write home about), but I think I can do better so I'm asking someone with more experience than I if they can tell what the issue(s) is(are) before I spend several days re-inventing the wheel (and wasting plastic in the process). Some of the objects have places along the perimeter that look like filament didn't get printed where it should. This doesn't continue around the entire object, just in certain places and not always on the same side and it doesn't appear to have a pattern. Also, something you don't see is that when printing the yoda figure, Slic3r decided it was a good idea to extrude filament in random "corners" on the interior of the object (both were printed with no infill) resulting in a big mess. The exterior looks okay, but if I wanted to eliminate the top layers and use it as a vase or something, it would be really ugly.

I'm using Slic3r 0.9.9 with 0.3mm layer height, J-head MK-IVB hotend (0.5mm nozzle), 0.42mm extrusion width, no infill, 3 perimeters. I have no "support structure" enabled in Slic3r although the yoda object STL I used had a built-in support for the chin. I'm using PLA with a 185 degree extrusion temp. There isn't any audiable skipping on the hobbed bolt like I reported before either and it is clean when the prints are done.

Have you checked the Gcode with a layer-by-layer Gcode viewer? That should easily show whether the incomplete perimeters are in the Gcode or whether the printer's extrusion is just not 100% reliable.

The other thing is probably the slicer enforcing the vertical thickness of the object's skin according to the solid top/bottom layer count. Does it put extra plastic where the model has slopes that are closer to horizontal than vertical direction? This is a feature, otherwise gentle slopes could have gaps (or very thin spots) in them unless you increased the horizontal perimeter thickness by a lot. It just doesn't necessarily play well with 0% infill.

what speed is your perimeter and infill?