One of the great things about 3D printing is just when you think you've got a pretty good idea of what's going on it throws you a curve ball. I'm printing a model that is mostly infill in PLA and about 1/4 inch up it stops doing the infill for no apparent reason. I wasn't watching it at the time so I don't know if it was trying an none was coming out or if it just didn't think I would notice. But as soon as I started watching again it started trying to do the infill. However, without a solid base to stick to it just made these wispy little threads across the infill area.
The print is finishing out fine, so there was no lasting effects from this infill gap, but still I wonder what caused it.
I'm planning on playing with HIPS next. I've got some cool disolvable ideas to try out. I'd also still like more likes on my book's facebook page. Sooner or later I need to get a contest together for that.