I am not a materials scientist or chemist. I found this page looking up some things for my linux distro.

I had, until recently, machined pure Teflon (PTFE) in industry. I know the MSDS sheets I was provided with mentioned, at least under heat of cutting, one thing it breaks down into (among others) was hydroflouric acid. Stuff you do NOT want to breathe! I know that as a highly poisonous acid that attacks glass.

Just my 2c from a non scientist prospective.

I had, until recently, machined pure Teflon (PTFE) in industry. I know the MSDS sheets I was provided with mentioned, at least under heat of cutting, one thing it breaks down into (among others) was hydrofluoric acid. Stuff you do NOT want to breathe! I know that as a highly poisonous acid that attacks glass.