Just a quick update as I still continue to enjoy using PETG.
Recently I had a go at testing how PETG goes when printing in vase mode.
For my first attempt, I was disappointed with the surface finish. There were numerous defects throughout the whole print that looked like “veins”. Close observations whilst printing leads me to believe that they occur when a small air bubble develops during extrusion. This air bubble causes a small ridge on that layer and as each consecutive layer prints the new extruded plastic is disturbed.
I tried printing another vase and there was a significant improvement in the surface finish. However, whilst the second print was running, I had to get some jobs finished and at no stage during the print did I open the printer’s door. I have a feeling that a change in air temperature may cause these surface defects to occur.
I have not had an opportunity yet to confirm if fluctuating air temperature causes these surface defects.
Regarding the mechanical properties of an item printed in vase mode, the strength is great. Each vase feels very strong despite being only 1 perimeter thick. The layer adherence of PETG is excellent and the vase has very good flexibility and strength compared to vases I’ve printed in ABS. I would compare the feeling of the vase to that of a plastic PET soft drink bottle (which should be expected because they are the same material) – similar flexibility in structure but the same ability to resist tearing.