Printing those propellers was a great success, but looking at those I could see space for improvement – those printing layers seem to be too obvious. Without any understanding if there is a real impact on a performance whatsoever I did some reading on this topic and except the obvious – sanding, there was a picture of using Acetone on ABS filament with very good result. So I bought Acetone!

Took a close picture of one of our propellers “before”:

Then I took one of kids brushes and applied it:

Well, that white colour – that came from that brush, so it doesn’t look well. On other hand there was quite a significant improvement in the surface smoothness!
I took one more picture, which is still not perfect, but already shows a bit of that “glassy” effect there.

Except that white part – I am happy and plan to apply this procedure on all propellers (which a clean brush).