White Spots on PETG

I was previously using hatchbox petg without any issue, but after switching to BL’s I’m getting these weird white spots on the bottom surface. Almost looks like dirty finger prints. I’m not adding anything to the plate for adhesive, so I know it’s not glue or another chemical.

Surely someone else has ran into this and has found a way around it. Otherwise back to hatch box.

you print anything in that same area recently without wiping the plate? or did it stick a little because it wasn’t cooled completely?

Yes I’ve noticed this also if I try to remove a print before the plate has fully cooled

I feel like I’ve gone back to prints a few hours after a print and still seen this, but maybe I’m forgetting. I’ll test this out a bit more.

I am getting the same on the newer texture PEI plate with black BL PETG. I let mine cool for about 12 hours over night and same results and I always use 91% IPA between prints. I am gonna test the older textured PEI plate and see if it does the same. Some other tests I’m gonna do is reduce first layer temp, change first layer print height. I might even try glue stick to see if creating a barrier might help.

I’ll report back

Yep, I tried again and waited and still saw some. I have a 3rd party plate I could try again, think I was having issues with that sticking before.


Gonna do a 4 layer high test of the old textured and this AliExpress one now.

This is what I get with the BL new textured (golden one). They are always wiped down with 91% IPA between prints. Never had the issue with any PETG except for BL but BL is higher temp then the average PETG. Hatchbox is around 230-240 where as BL is more 260c

Both plates did it still.

I stopped testing. I hit it with a heat gun on low for 5-8 seconds and gone. I’ll just do that. Was stupid easy.


Right - just saw this thread and wanted to write it: I always use a heat gun for a few seconds to wipe away white marks on the bottom side.