I turned down a gallon (opened) and the rest of a case - 4 total that was
Semiconductor / lab grade HF.

Reason - I know the stuff. I don't consider it over other acids.

HF will 'fly' through your skin and body - attacking the joint by dissolving
the calcium components of your joints. The joints begin to grind and are
forever bad. The cartilage is jelly. Be sure you know what you are
doing and protect yourself. It fumes and must be treated as dangerous.

I left the bottles in the semiconductor lab for hazmat to clean up. We were
moving out of that building and the semiconductor lab dissolved semiconductor
with it. It etches glass so special handling is needed.

Martin

Ed Huntress wrote:
"Richard J Kinch" wrote in message
. ..
Ed Huntress writes:

I thought that's why people used hydrofluoric
acid for small-batch passivating. Hot nitric is very nasty stuff.
And cold HF is even nastier.

But isn't it safer to handle, at least because of the cooler temperature?
And how about the fumes? I don't know the answers to these questions; I'm
just asking.

The only hydrofluoric I've been near is the pasty stuff that comes in a
tube, which you can get at your local welding supply. But I only needed a
dab of it.