wrote:
Have you ever heard of this stuff?

https://en.wikipedia.org/wiki/Potass...e#Applications

There are not enough hours in the day for me, I do not have the spare time
on my hands to post unrelated stuff to a cycling group.
I'm 66 this year, would you offer me a job that I do not want or need?
As for your link, K Class is F Class in the UK ...........as far as I
remember from what is now a distant past.