I wanted to share my finding on this issue in case it helps anyone else.
I have been printing production parts with the Tinmorry CF-PETG with little to no issues but wanted to try the Bambu Lab PETG-CF because it’s quite a bit cheaper with the bulk refill pricing. My first impression was that I really like the more matte/textured look vs the Tinmorry but like many others I was having issues with heavy buildup on the nozzle. Changing various slicer settlings had little impact. I was using a 0.6 E3D Obxidian nozzle which is supposed to be one the best as far as non-stick properties.
I then decided to try some different nozzles and the results aren’t what you’d expect. First I tried an E3D Nozzle X with some Slice plastic repellent paint applied and the results were much better but still had some buildup.
Then I tried a cheap Amazon no name 0.6 steel nozzle also with the Slice plastic repellent paint. Running the same gcode I’m getting prints with virtually no buildup at all. I also tried the paint on the Obxidian nozzle but it did not help.
This is the Obxidian nozzle after around 5 minutes of printing.
This is the Amazon nozzle with the Slice paint after a 2 hour print.
I’ve seen theories that the Bambu filament could have some magnetic properties and it seems like that could be the case. Depending on exactly what type of steel the nozzle is made of it could possibly cause it to stick more. It’s also possible that the coatings on the Obxidian or Nozzle X make the Slice paint not work as well. I don’t have any other nozzles to test with at the moment. Hope this helps.