For the first time, I bought Bambu Lab PETG-CF and printed a poop deflector and box for my A1 mini.
The walls and top surfaces were of excellent quality. However, I was surprised at how bad was the bed-facing surface (textured plate). In all my prints, there were huge white patches (see the attached pictures).
None of this ever happened when I printed in PLA. The only PETG I have experience with is the Bambu Translucent one and everything is fine there.
Would you please advise on what may I have done wrong?
I used 0.4 mm Hardened Steel nozzle and explicitly set the PETG-CF filament in Bambu Studio. I have used no glue on the bed. Even though the print was more difficult to release from the plate compared to PLA, it was not that bad - a bit of plate bending and eventually the prints fell off.
The petg is sticking too well to the bed, and the filament is being sort of stretched at the surface. You can remove the marks by heat or solvent. In future use a glue stick or hairspray as a ‘tearable layer’ between the print and bed. That may destroy the pattern on the baseof the print. Perhaps put the plate and object in the freezer, before flexing.
As @debonr said, its due to bed adhesion scarring when removing. I’ve ran a flame over mine and they fade away with the right balance, heat gun may work just as well but I like fire
This happens pretty much every time I use Bambu’s PETG-CF. I use one of those Hacksmith mini-lightsabers to (carefully!) apply fire to the bottom of the object. Within a second or two, the white marks disappear. Be careful and don’t hold the flame there for too long - you don’t want to melt the thing! Also, please wear some gloves in case you momentarily do something stupid. Ask me how I know… LOL
Just to add, in some extreme cases where I know the plate has been grippy to a fault I’ve given it a real light mist of hairspray the next time and it comes off a lot easier.
The glue stick did an excellent job. I just applied a very thin layer, spread it evenly with my finger, and the dark carbon fibre filament was amazing straight after getting off the plate. The glue washed away easily using soapy water. Amazing. I don’t know why I was so hesitant to use the glue stick.
The fire treatment worked well on thick models. I used an old-fashioned lighter and all was good.
However, in the case of the poop box that’s got very thin walls, the bottom started to warp immediately once applied a bit of heat. Just writing this for anyone else to be careful
I’m glad it’s something that’s normal. Will try out the fire treatment!