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That's why you keep calcium carbonate salve around. Also you're more vigilant around hf. I've spilled conc sulfuric and nitric acid on my lab coats. HF will

That's why you keep calcium carbonate salve around. Also you're more vigilant around hf. I've spilled conc sulfuric and nitric acid on my lab coats. HF will never get that close, as safe equipment is in a closed loop but not that complex or byrdensome (it's not like explosives research for example) There are some idiots that use open air HF for etching. That is a very bad idea. I should clarify by open in the description I meant valve open. The system was still closed.

whatshisface 7y ago
But who had to carry the jar of HF into the lab and attach it to the closed system?
- dnautics 7y ago
  It's a gas canister, there are extremely secure valves. I've done it myself.
  - omar_a1 7y ago
    As in, a highly pressurized gas canister? In a container that is presumably 100% impervious to HF corrosion, yet somehow also made out of a material that can withstand those pressures? How is that safer than neutral-pressure, aqueous HF? I'm perfectly comfortable with bottled HF, to the point that I literally handled it in the dark (light-sensitive samples), but I'd never set foot in the same room as a pressurized HF gas canister. A spilled HF bottle is a major incident, but ultimately straight forward to contain, whereas an HF canister leak would kill off an entire lab. I've done enough manifold setups and worked with enough gas cylinders to understand that they can leak in all kinds of ways, even with a wealth of experience. As I said initially: you are definitely not paranoid enough about this setup.
    - ovi256 7y ago
      This also begs the question of whom exactly has an unobtainium pump that can withstand HF to put it into a cylinder.
      - dnautics 7y ago
        I'm just going to say that your ignorance about HF is exactly my point. 100% HF is obtainable commercially in labs and only requires shipping precautions on the order of what you would expect for toxic volatiles.
    - Karunamon 7y ago
      Derek covers this in one of his articles. [1] >It’s sold compressed in metal cylinders, like other gases, but it needs some care in packaging. The stuff is so corrosive that special alloys need to be used, usually ones high in nickel. If you stick an ordinary gas regulator on top of an HF cylinder, you’re in for trouble, and the complete destruction of the regulator is the least of your worries. >HF has actually been used right out of the cylinder for a long time in Merrifield peptide synthesizers. [1]: https://blogs.sciencemag.org/pipeline/archives/2004/03/03/things_i_wont_touch_1 https://blogs.sciencemag.org/pipeline/archives/2004/03/03/th...
refurb 7y ago
Fair enough. You’re using it in a certain way that makes accidental exposure less likely. I was speaking more generally. It’s not uncommon for labs to handle concentrated HF in a similar manner as other acids - I.e. pouring it into a beaker in a fume hood
- dnautics 7y ago
  Yes this is a mistake but to categorically say that HF is scary and dangerous actually creates, in my opinion, a mindset that is detrimental to operator's of safe HF equipment and also encourages use of more wasteful (e.g. FMOC) techniques which also have tradeoffs (nonsynthesiazbility is more of a problem with FMOC than BOC). And I was clear that setup matters in my gp.

whatshisface 7y ago

But who had to carry the jar of HF into the lab and attach it to the closed system?

dnautics 7y ago
It's a gas canister, there are extremely secure valves. I've done it myself.
- omar_a1 7y ago
  As in, a highly pressurized gas canister? In a container that is presumably 100% impervious to HF corrosion, yet somehow also made out of a material that can withstand those pressures? How is that safer than neutral-pressure, aqueous HF? I'm perfectly comfortable with bottled HF, to the point that I literally handled it in the dark (light-sensitive samples), but I'd never set foot in the same room as a pressurized HF gas canister. A spilled HF bottle is a major incident, but ultimately straight forward to contain, whereas an HF canister leak would kill off an entire lab. I've done enough manifold setups and worked with enough gas cylinders to understand that they can leak in all kinds of ways, even with a wealth of experience. As I said initially: you are definitely not paranoid enough about this setup.
  - ovi256 7y ago
    This also begs the question of whom exactly has an unobtainium pump that can withstand HF to put it into a cylinder.
    - dnautics 7y ago
      I'm just going to say that your ignorance about HF is exactly my point. 100% HF is obtainable commercially in labs and only requires shipping precautions on the order of what you would expect for toxic volatiles.
  - Karunamon 7y ago
    Derek covers this in one of his articles. [1] >It’s sold compressed in metal cylinders, like other gases, but it needs some care in packaging. The stuff is so corrosive that special alloys need to be used, usually ones high in nickel. If you stick an ordinary gas regulator on top of an HF cylinder, you’re in for trouble, and the complete destruction of the regulator is the least of your worries. >HF has actually been used right out of the cylinder for a long time in Merrifield peptide synthesizers. [1]: https://blogs.sciencemag.org/pipeline/archives/2004/03/03/things_i_wont_touch_1 https://blogs.sciencemag.org/pipeline/archives/2004/03/03/th...

refurb 7y ago

Fair enough. You’re using it in a certain way that makes accidental exposure less likely. I was speaking more generally. It’s not uncommon for labs to handle concentrated HF in a similar manner as other acids - I.e. pouring it into a beaker in a fume hood

dnautics 7y ago
Yes this is a mistake but to categorically say that HF is scary and dangerous actually creates, in my opinion, a mindset that is detrimental to operator's of safe HF equipment and also encourages use of more wasteful (e.g. FMOC) techniques which also have tradeoffs (nonsynthesiazbility is more of a problem with FMOC than BOC). And I was clear that setup matters in my gp.