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Comment by knolan | Hacker News Reader

HF is extremely scary, the safety precautions taken to work with it at an acid bench really bring this home.

I heard a story once of a student putting a bottle into his backpack and cycling across the city to another university building to use it in another lab. The mind boggles at the stupidity.

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I used HF to clean the surface of a copper scattering cell (block of copper with an internal chamber and some access ports, about 5 inches high and 4 across).

Burn cream on hands, two pairs of gloves, one silk one leather, leather apron and splash goggles. Comes packed in a plastic container which is secured to a small wooden pallette with the bottle held upright in a box with wooden batterns. Impressive warning signs.

OA has solved the mystery of why we had to use these precautions!

It is indeed scary. I once had to use a mixture of boiling nitric, hydrofluoric and perchloric acids... quite possibly the nastiest stuff I've ever come across, and partly responsible for my sideways move into programming.

The lab had a shower cubicle in the corner, with a tank on top and pull handle. The idea was that if you got any on you, taking an immediate shower in caustic soda was the best thing to do...

When I was a school kid, a friend and I were into blowing stuff up and general chemical mayhem (those innocent pre-9/11 days!). We used to synthesize fuming nitric acid and mix it with oleum and potassium permanganate. The resulting fuming, purple mix would cause pretty much anything it came into contact with to immediately combust.

But that sounds - if you'll pardon the pun - like child's play compared to your boiling(!) nitric, HF and perchloric acid. I cannot image how you'd even contain such an evil substance? And what was it used for?

We mixed it fresh every day, and to contain it we used crucibles made from a platinum/gold alloy. Which, needless to say, were locked away very carefully at the end of the day.

And I was using it to dissolve up rock specimens for analysis: basaltic lavas that contained chromite and other notably insoluble minerals.

That stuff would dissolve anything...

One of the labs where I first had those (also chip fabs have them) attached to a high flow water supply - normally triggered by standing inside them.

Our top H&S guy decided that as he was responsible he should be the one to test it he did cheat a bit by wearing swimming goggles to protect his eyes. He commented it was like being sand blasted with small ball bearings and "fracking hurt"

A long time ago (late 70's) a lab I worked next to had an emergency shower over each worker and there were straps on their wrists. If they jerked their arm back the shower would go off.

When I was in high school in chemistry class I accidentally picked the wrong bottle of sulphuric acid to use in an experiment - I remember thinking "this stuff actually seems to be viscous" and "why is everything getting so hot" before the explanation dawned on me....

So why the hell was it sold as a commercial rust remover product?

Key word is "commercial". The commercial world is full of dangerous substances (when you leave the safety of an office and go into the dirty world of production :-)), out of necessity, but you are assumed to have received proper training and be in possession of proper safety equipment.

Concentration has a lot to do with it. More dilute solutions of HF may cause burns, but t it's unlikely to kill you.

Concentrated HF is another beast entirely.

And given that it was in an old dusty bottle packed away deep, it may have concentrated over time due to evaporation.

Acids tends to pull moisture from the air (hydroscopic) and dilute rather than lose water and concentrate.

I'm guessing it came from "another era" where you could buy stuff like this without an issue?

But even few years ago I visited a wolfram mine in Portugal on a job, and was told by the guy I worked with at the time that the miners are using stuff "banned long time ago in UK" to clean the tips of the guiding ropes which we were replacing. I was never told what it was, but nowadays I suspect it was HF.

For those who might be confused, "wolfram" refers to Tungsten.

"Commercial" just implies commerce; that it was a product that could be purchased. It was not a consumer product. In the article it says the title was "Industrial Laundry Rust Remover".

There are certainly much nastier chemicals used that this in industry. As an example, I'm reminded of a quote by Gordon Moore about Intel having melted their sewer pipe, in this article:

https://www.bloomberg.com/news/features/2017-06-15/american-...

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