ZiggyNZ

The original cubes done with Cura look as though there could be over-extrusion? If so, all the walls would be squished out slightly. If the cube is slightly wider than it's supposed to be on the sides, the effect would be compounded on the corners and they would gradually try and climb up... which is what we see. Nice to see that you *did* get acceptable cubes in the end.

Hi Dave. I haven't tried PETG yet, but recently set up an Ultimaker Original +, and am using Cura. Had lots of issues with stringing (and other gremlins too) with some filament, and found this guide http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide was really handy - seems likely to apply to any printer, and its fixes refer specifically to Cura settings. Cured my stringing problems in the end by enabling retraction, enabling Combing mode, and lowering temperature (190C with the problem PLA). Found also that it was very filament batch dependant: although this was with PLA from a reputable supplier, their grey performed very differently to other colours which were OK at higher temps. Will be interested to see how you get on with your open frame! Let us know how it works out for rigidity. I picked my printer kit in part because I liked the idea of solid-ish walls (plywood, in my case) to get rigidity, and it's easier also to fully enclose the printer to run ABS print jobs, which I'm tending to do when I need "strong". Looking forward to your updates, and I wish you every success at this.

Brilliant! This is the master class in how to use 3D printing for ATM. Thanks for sharing the pics. Now trying to figure out how I can make something similar for my new 10" f5.6 mirror.