On 19 Jul 2008 11:44:22 GMT, (Andrew
Gabriel) wrote:

Small quantities quickly cause bone destruction.
I think it's only a catalyst, so it's not used up
in the process and can just cary on going.

It's not a catalytic reaction, but as you point out it's
self-regenerating and so it does carry on until you take action to stop
it.


Hydrofluoric acid used to be used to make frosted
light bulb glass.

Still is. Hydrofluoric is used to etch, then bifluoric (which leaves a
smooth surface) is used to "polish" the etch a little, giving dispersion
without much loss.