PETG as support for PLA

  • This has very little to do with Duet so if it shouldn't be on this forum, please disregard or delete ....
    I am trying to use petg as support for a PLA print which many people on the internet feel is a good way of going. I have had zero success and am wondering if anybody uses that combination, if they could post some printing parameters.
    More specifically, I find that PLA doesn't stick at all ... like zero... nada to petg. When I try to print pla over top of a petg roof support, let's say in a zig-zag pattern, I get basically loose bits of pla lying on top of the petg. By the time the second zig-zag layer gets printed, the individual bis of pla from the first layer tend to be pushed around by the hot pla from the nozzle and tend to bunch up making a gawd-awful mess out of the entire thing.
    What (if any) is the trick to getting the pla sticking at least a tiny bit to the petg so that the second layer has a bit of a firm base it can build on?

  • What are your support separation settings? Close to zero separation distance might be best, considering the poor adhesion.

  • Good point - I had it set for 0.2 mm which probably gets rounded up to normal layer height.
    Thank you, I will give that a try!

  • Moderator

    Totally acceptable content for the forum. Moved to 3D printing general chat forum though.

    I'd think you'd have to go incredibly slowly and close to give the PETG a chance to heat up a bit for the PLA to tack to it.

  • @jens55 said in PETG as support for PLA:

    What (if any) is the trick to getting the pla sticking at least a tiny bit to the petg so that the second layer has a bit of a firm base it can build on?

    print slow, print hot. I was using ABS as support for PLA back in the day but gave up as while acetone dissolves ABS and does not dissolve PLA the PLA I was using back in the day got "crumbly" and "ugly" and failed after few days after being soaked in acetone so I gave up on the idea... (abs with hips or hips with abs is much better idea) and the solution was same, you print it hot and it will stick ... and of course, you need to set zero layers separation in slicer

  • I just finished a test print with 100% success. Thanks for the suggestions.
    I think the major problem was that I never removed the gap from when I was printing both the model and support with pla. I had completely forgotten about this.
    I also printed slower although I don't actually know which of the many speeds is used - I suspect it was 26 mm/sec for petg and pla at 40 mm/sec.
    The petg and pla stuck together to a limited degree ... enough to hold everything together yet not so much as to make support removal difficult.

    I only have two words ...... Woooooo Hoooooo !

  • Just a quick note that I am trying the support thing again and this time I have zero success with a zero thickness gap between interface layer and model. The issue is not one of separation but one of an unusable messy print.
    The old thread is here :
    [link text] url)

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