[sprotz]

I would buy the fluoride but most online stores either don't ship internationally or have too expensive shipping costs, so I thought it would be easier and cheaper to make my own. I heard that pyrolysis of PTFE / Teflon tape would give hydrogen fluoride as one of the byproducts and when dissolved in water will give hydrofluoric acid and reacting that with lye will give potassium fluoride. Is this a viable method? Or perhaps combustion of an HFC refrigerant would also give off HF that I could use to make the fluoride ?

[mjc123]

Don't do this as an amateur! HF, whether gaseous or aqueous, is nasty stuff - very corrosive and toxic. Do NOT work with HF unless you REALLY know what you are doing, and have all the right safety precautions in place. (Can you get HF antidote gel, for example, or would that have to be shipped expensively from abroad?)

[sprotz]

Almost everything has to be shipped in, is it because of the pandemic? I know the dangers of HF and other corrosive chemicals. I've worked with chlorine leaking into the room for example, I wonder if working out in the open is a safer alternative. 

[wildfyr]

I've worked with chlorine leaking into the room for example,

This does not inspire confidence.

[Enthalpy]

PTFE pyrolysis produces things even worse than HF. Efficient carcinogens, among others. DON'T do that.
Same for the combustion of HFC.