I like the thermal mass of glass for temperature stability, as I’ve found that’s pretty key to getting good print adhesion. But I really wanted to try out PEI without having to stick a giant magnet directly to my heater plate, something I definitely did not trust.
Turns out, you can solve both problems! This was how I did it.
Probably not in general, but it seemed like it’d be a massive pain in the arse to get back off if I didn’t like it. I’d been getting pretty good results with coated glass and didn’t want to have to worry about going back.
Also, I could lose the thermal momentum and heat evenness I was seeing with underbed insulation and a glass bed. (I brought that post over too, separately.)
Also also, I hear a lot about warped and/or warp_ing_ heating plates, and glass doesn’t have that issue.
So basically it’s a stabilising element at a cost of a little more heating time and increased chance of ringing if you overdrive your bed speed.
I do have to say that I’m finding PEI to be better than coated glass in most ways, but it’s also a lot more fragile and will clearly wear out sooner. Which is ironic - a metal thing more fragile than a glass thing - but there you are.