I just read this topic, and wanted to throw something out there about HF. I worked in the semiconductor industry for 40 years, and have extensive experience with both Hydroflouric Acid, and Hydrogen Flouride gas. It is used to eat away glass or Silicon. I have been burned by it, and I have seen the horrors done to the unfortunate who have been burned worse than myself.
HF is known as the "Bone Seeker". Abut 30 years ago when I got burned, I had acid gloves on, but there was a pinhole leak. I was replacing filters on an acid sink, and the acid leaked into the thumb of my glove. I did not notice it for a couple hours, until my thumb started feeling sore.
I took my gloves off and found my thumb wet, and wiped it dry with a towel, then did the taste test, (the illegal but often used tongue tip and spit, technician method) and sure enough I tasted acid. It tastes like vinegar.
I was unfortunately seen and snitched off, and the Intel fab police caught me and threw me into a cold acid shower for 15 minutes, and stole all my clothes , my wallet, everything, and bagged as hazardous waste. They sent me to their onsite clinic, where they made me rinse my hand for 15 more minutes, then wrapped my hand with Magnesium Oxide paste and bandaged.
At this time, my thumb felt like someone had whacked it with a hammer. They told me the HF had went right through my skin as though my skin was no more than a sponge, and was etching the bones in my hand. Intel takes HF burns VERY SERIOUSLY!
The next morning my thumb was throbbing, and I went into the clinic to get repacked, and when they took the bandage off, my thumb was purple. In a couple days, the thumbnail fell off. A week later, X-rays showed my thumb bones etched thinner than normal, and I was considered recovered. I was lucky it was a minor burn. The skin was just fine, but bone and fingernail were eaten up.
HF smells similar to Chlorine, and Bromine, and if you smell it, exhale it all, run away, and inhale from somewhere else. I am sure the Semiconductor industry grade is more concentrated than people will encounter in the outside world, but I would not take a chance.
In 1978 I got a job as technician at Siliconix, and they guy who cleaned the glassware there had one normal arm, and 1 super skinny deformed arm, he had HF pour down inside his acid smock sleeve, and though it was just water for several minutes until he realized something was wrong. They had to separate his muscles from his bones to pack magnesium paste around them to save his arm.
HF is serious. I did not know it was in these batteries. Use a plastic tub, plastic is safe, but glass is not. Glass Etching cream for hobbyist has HF in it. Also, Fluoride in drinking water and toothpaste is supposed to be safe?
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