G’day; If almost any fluoride (calcium, sodium, potassium, etc) is heated
gently with a little 10% sulphuric acid - or even sparex, hydrofluoric acid
will be generated. I happen to use an excellent flux called "Easy-flo"
which contains a small quantity of a fluoride, and if you were to have a
look at my pickle pot when clean and dry (not very often, that) you would
see that the inside has a frosted appearance, where the acid has combined
with the fluoride in the flux to etch the glass surface. Thus, a fluoride
plus an acid will etch away porcelain, clay, glass, fired enamel, etc in a
very controllable, and not particularly hazardous way. Is this esoteric
any use to anyone? Cheers
/\ John Burgess
/ / Johnb@ts.co.nz
(_______) It's springtime in Mapua Nelson NZ. Stroll
through the village and you can (almost) hear Johann Strauss’s
’Voices of spring’!