Polypropylene? Interesting. I print on PEI coated spring steel or glass. The glass carborundum bed was ok for a while but seemed to wear out as eventually I'd have a lot of adhesion issues.
I print in my basement which is about 65 in the summer and 60 in the winter. For PLA I print at 60C bed, 209 Nozzle. But all that depends on machine, speed, hot end type, etc. I find a lot of issues come with drafts, as it leads to uneven cooling. If need be, you can use a wind block if it's from a known source or a cheap to free enclosure.
PEI impresses me, but I'm always willing to try the next best thing if it's affordable. I may try those garolite boards. I like the idea of a lightweight solution, as I'm going to go klipper on one of my printers, so anything to reduce vibrations at high speeds would be a good thing.
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