[Mdemon]

Imported post

OK, so Welder's O2 might have traces of acetylene in it. Is acetylene poisonous?  Are there any purity tests or would breathing a tin of it on dry land be the only way of testing it?

What else could there be (unexpectedly) in O2?

He - seems to be supplied as either pure or mixed with air.  What nasties could we expect to find and would the air be "clean"?

I know a lot of guys have been down this route so what is the concensus?  PM if you prefer...  

 

[Alan57]

Imported post

I've been mixing trimix in my garage for about 3 years. I used to buy 99.995% O2 but have for 18 months used 99.5%  without problems its less costly to buy - called 2.5 O2 and comes in a 47l at about 220bars. I think the acetylene story is an urban myth.
My He is 99.996% (He 4.6) and is in a 220bar 50l botle commonly referred to as a J bottle.
The O2 is 18.77UKP and the He 120.57UKP when bought in July 2003.
I've not experienced any respiratory, odour or explosive problems yet!
Alan

 

[Mdemon]

Imported post

Cheers Alan - that's what I wanted to hear.  

 

[bang-on]

Imported post

Quote[/b] (Alan57 @ Feb. 05 2004,21:51)]My He is 99.996% (He 4.6) and is in a 220bar 50l botle commonly referred to as a J bottle.

<font color='#0000FF'>also check for parts per million of hydrocarbons,to keep everything o2 clean.
most gas stations with have a spec sheet on the gases and some will do custom mixes at a price.
the best i can get is 200bar?
he has just gone up to £107 +vat for a j.
cheers
barrie

 

[Mdemon]

Imported post

Bang-on mate, what level of hydrocarbons should I looking for - zero?

 

[Mark Chase]

Imported post

Welders O2 does NOT have acetylene in it. That comes in a separate bottle and is no way associated with the production of O2 in the factory. The level of hydrocarbons is the only thing of any concern and the level of water vapour. I understand that medical grade 02 has a higher level of water vapour in it.

The only thing to avoid totally I am told is balloon He as I understand it has a breathable level of o2 in it to stop people hurting them selves so its in fact 16/84 straight out of the tin.

ATB

Mark Chase

 

[Paul Oliver]

Imported post

M

We have used "welders" O2 for years, no problems other than weight gain and hair loss. We generally buy whatever we can get a deal on.

Not got into He mixing yet, but that will come in time.

Dive Safe

Paul

 

[Dominic]

Imported post

Acetylene spontaneously explodes when under pressure. There is NONE in any Oxygen cylinders you may be given. Gas manufacturers aren't suicidal.

The only real difference between different grades is the amount of paperwork and testing done on it, along with anything the companies deliberately put in - such as water, in some cases. Oh, and a few places empty some cylinders to ambient (1bar) and others to vacuum (0bar)

It all comes out of the same supply. Phone them up and ask about the differences - unlike dive shops, they'll actually tell you

 

[dlegros]

Imported post

Quote[/b] (Dominic @ Feb. 06 2004,10:39)]The only real difference between different grades is the amount of paperwork and testing done on it, along with anything the companies deliberately put in - such as water, in some cases.

I remember this being discussed in an O2 admin course.

I think the verdict was a combination of the above points.

Medical Grade has a slightly higher water vapour content (the respiratory tracy prefers moist gas - that's why we humidify high percentage O2 in hospitals).

Also, medical grade is tested in every cylinder, whilst welding O2 is tested on a batch basis.

HTH

Dom