Refrigerant tank

I don't think so but the regulations governing the release of CFC's to the atmosphere will be violated. How empty is empty? I'd open, then remove valves and open vent for a day or two rather tha dive straight in with an angle grinder.

I don't know about the modern non CFC refrigerants, but if they are old enough to have contained refrigerant 12 (Freon) beware; R12 + heat = Phosgene!

I know you are into re-enactment and all that, but a mustard gas attack in Bristol may not go down too well ;-)

Yes ! OK, so the real risk is small. But _I_ won't cut these, and I'll cheerfully do propane. Having said that, I do have a nice big one (100lb BCF extinguisher) that I'm planning to turn into a sword forge. I'll be wearing BA kit when I do it though.

You won't make mustard gas by this route - but then if you needed mustard gas around Bristol, you could just go and dig it up.

"Andy Dingley" wrote (snip):-

Now I'm intrigued, I actually thought heat decomposition of a halogenated hydrocarbon to something nasty(er) was a pretty remote possibility and really only mentioned it to be a smart a**e! Should we be wary of Philip T-E on a hot day?

Only if you're downwind of me :-))

Regards

Philip T-E

And not necessarily on a hot day !

Regards

JohnR

It came off my tame mechanic's scrap pile & he renewed the bottle yesterday. I'd be surprised if its more than a few weeks old. Certainly not Freon, he told me ages ago that it was no longer available & the new stuff was tetra - something.

Regards,

J. Kim Siddorn,

"Kim Siddorn" wrote (snip):-

This stuff perhaps?

Thanks, interesting stuff. You never stop learning 'till they screw the lid down and hopefully a few precautions will ensure that that time remains firmly in the future!

It's going to happen, the question is how much. In fire extinguishers, the ones that are still available (albeit rare) are the halon that's "low fume" (Halon-1401 ?) and suitable for use in aircraft (which are hard to vent at altitude). The more common Halon-1211 stuff, as many of us still keep on hand for real car or workshop fires, is distinctly unhealthy in a confined space.

Go back to the formulations of the '50s or earlier, especially the old Pyrene carbon tet extinguishers and it's fecking poisonous! Old safes are another one with a toxic hazard if you start hacking around with a gas axe (tear gas grenades).

Of course concentration makes a huge difference. Spraying a full cylinder onto a fire is a lot different from traces adsorbed onto the inner surface of an "empty" tank. After all, it's not fluorides or something _really_ dangerous to heat up, like Easyflow flux. However these aircon refill tanks are pretty flimsy and I'd much rather use a propane cylinder for the job, avoiding the problem altogether. If there's one I really want (like my forge casing) then I'll just rubber up to deal with it.

I was casting bronze at the weekend

Thanks to all - as useful a resource as ever!

Regards,

J. Kim Siddorn,

Err - actually yes it is fluorides (or organofluorine compounds, same difference) which also give off HF hydrofluoric acid gas when over-heated. But as you say the quantity will be small.

The containers will have a "R" number on them - at least I've never come across one that hasn't, and I think it's a legal requirement. Can you tell us what it is?

btw, 1,1,1,2 tetrafluoroeth_a_ne (CF3-CFH2) is not the same compound as unpolymerised (poly-) tetrafluoroeth_e_ne (CF2=CF2).