PETG sticks to Glass Bed too well?

[pochrist]

I have been learning to use my new 3D printer since early December and have finally correctly calibrated and it and level the bed, (went for 2 weeks with poorly leveled bed and experienced failed prints due to lifting edges and such). I went fro the last 3 weeks printing PLA and just went back to playing with PETG and have a slight problem:

Important note: I use a heated glass bed with NO additional adhesion (ie. hairspray, glue tape, etc) I know many are fans using these products (or forced to because they lack a heated bed) but I have been able to get by with keeping the glass clean, I think it gives a nice finish.

Anyway; if i print with PLA I can wait till the bed cools and then it will pop off by itself, but I find the PETG sticks real good (so much I'm afraid I might crack the glass). I print with a bed temp of 85c. Should I let the bed cool more (like say put it out side where it cold 20 degrees Fahrenheit currently) or maybe heat up the bed to 95c perhaps to see if it will loosen up?

[KDog]

Try putting it in the freezer for a bit. My PETG prints pop right off after it gets cold. I use purple gluestick on the glass. It might make it a bit easier to come off.

[curious aardvark]

85 seems a bit hot for petg to me.
I run mine at 70c.

The other thing you can try is a sharp tap with a small hammer often knocks the print loose.

But it does sound like you're not waiting for it to cool down enough. If the glass plate is removeable, you don't need to leave it outside. Once ity's off the hotplat it'll cool down pretty rapidly.

[Todd-67]

Yes you are not letting it cool long enough. You can also adjust the first layer height a bit to keep from driving the plastic into the bed so hard. The freezer trick works well also. I use it quite a bit with ABS.

[3dex ltd]

Yeah easiest way to get a print off a bed is to cool it right down. Spraying compressed air onto the base of the print will have a cooling affect and should work perfectly.

Be careful as if you cool a glass bed too much it can crack.

I find pushing a sharpe knife between the print and the bed whilst cooling the print also helps.

Regards,
www.3dexfilament.co.uk

[wirlybird]

Check the first layer height. PETG doesn't like being squished (70 on the bed). I print larger items in PTEG on PEI with a bit of glue stick and it releases pretty good. I also use a "sticker scraper" single edged razor blade in holder to release prints. Works well but be careful.