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For every % of contamination the quality weld diminishes. This is in both oxygen welding and cutting and the use of gas for shielding. Industry does not throw money out the window. ----- Original Message ----- From: Hans Petter Roverud <proverud@on*.no*> To: Aldo P. Solari [APS] <aldo.solari@ho*.se*>; <techdiver@aquanaut.com> Sent: Sunday, October 01, 2000 5:27 PM Subject: Re: welding He good ? > According to my gas supplier there's one grade we should definitely avoid, > namely balloon helium. They receive helium as cryogenic gas and evaporate > it to fill storage cylinders. The first batches of this distillation > process will be sold as balloon helium since it tends to contain > impurities. In some countries they add a little oxygen to balloon helium to > avoid the risks of hypoxia if people breathe it but that's another issue. > Expect balloon helium to be impure while all certified grades should be OK. > Check the specs of welding grade in your country and be particularly > concerned if it allows CO2. (Typically, impure helium may contain neon, > methane and CO2). > > regards, > > Hans > > At 04:27 AM 10/1/00 +0100, Aldo P. Solari [APS] wrote: > >Dear senior tech divers: > > > >Some of the senior tech divers stated that "welding helium would be > >good for diving mixes/breathing". > > > >In Canary Islands (1200 km from nearest euro port), there is no > >"medical grade" Helium but there is He for welding (it comes in > >50 Lt tanks and the cost is around 355 USDollars each). > > > >My questions are as follows: > > > >(1) Has any one run any anylses (gas chromatography, whatever) on > >welding grade helium ? > > > >(2) Those of you who have used welding grade He: do you use any > >special filters to clean up impurities ? > > > >Any other info would be mostly appreciated. > > > >If welding He is enough good, it would open up a new world to > >divers on the islands, here. > > > >Thank you for your comments. > > > >cheers, > > > > aldo > > > >aldo.solari@ho*.se* > >www.ccbb.ulpgc.es/fish-ecology/solaris > >___ > > > > > >-- > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > -- > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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