I have been printing with PETG on glass for a little while now, and have gone through almost an entire roll. Yesterday I had my first print stick so hard that it delaminated the glass :(. I stopped using hairspray as it made the prints not stick at all, and printing bare glass was just fine. But something about yesterdays print made the glass give up. Is this how PETG + Glass normally fails? Works perfectly for years, and then suddenly fails?
Windex and gluestick are other options besides hairspray. And yes, you experience is not uncommon.
Never tried Windex, but might give that a go. Gluestick had the same issue, lots of prints wouldn’t actually stick so I had lots of failures :/ I vaguely remember someone suggesting sugar water, so might try that as well.
Windex to clean, let it dry for a bit, then a layer of gluestick has always worked for me, as long as the bed heats to 60°C for printing. The z offset has to be a bit different for PETG than PLA, which can be a bit tricky. I think (been a whole since I’ve printed PETG) it had to be a bit higher than PLA, so it wouldn’t “squish” as much as PLA. Seemed a bit counterintuitive, but it solved most of my problems