Let’s recount the events so far.

Printer was printing fine in PLA on the textured glass surface (with a minor elephants foot type thing at the bottom of the print).

I switched the filament to PETG and turned the glass plate to the smooth side, and coated it with some Pritt-Stick to protect it a bit.

The printer printed the PETG very well, although with a similar minor elephants foot type effect. Printed a Benchy.

I managed to print the first two pieces of the mould pretty well, no complaints.

In removing the second mould piece from the bed I stabbed myself in the hand.

After stabbing myself I decided I needed to cover the bed with tape or something to reduce the stiction. This yielded alot of loose filament when the printer was doing the second layer. Not ideal.

I calibrated the extruder which was previously printing only 93mm per requested 100mm. From this point onwards it was calibrated for all prints (once I realized where the config save button was. Pretty smart using the SD card instead of explicit EEPROM I must say).

Stringing continued.

Things I have loosely tried include:

  • Kapton tape instead of frogtape
  • Going back to glue instead of tape
  • Cleaned nozzle and extruder
  • Increased Z offset between 0.02 and 0.06
  • Recalibrate extruder (was fine)
  • Varying methods of bed levelling
  • Lowering fan cooling
  • Increasing printing speed

As it stands I’m about to try printing with a 90% flowrate on the extruder during top and bottom infills since this is where the problem is. Also going back to a frogtape bed. PLA is a little stringy now in the same place, perhaps overextrusion since before I calibrated the extruder properly the PLA was going fine. Heard somewhere that PETG wants a little underextrusion and a bit of Z offset so will try that.

Some Success

Reduced the top/bottom flow to 90% and suspected minor improvement.

Decreased it to 84% and has attained significant improvement but still a little stringing/overextrusion.

I shall try reducing further to perhaps 80%.

Am also losing 0.5mm in height on all prints. Probably something to do with the interface between print and bed. Will confirm the cause once I solve the slight lifting issue that comes with using such narrow tape. Wider 2” tape ordered. 3” was too expensive.

Expect some post with the cura profile to follow. Mostly for my own reference but it might be of use to someone somewhere.