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> > Jon Guizar wrote: > > > > With regards to the helium purity issue: > > > > > > > > If you establish a good working relationship with your supplier and you do a fair amount of diving (buy lots of gas) you can easily work out a good price for the helium. I purchase 300cf fills for $50. > > > > If anyone has had problems from medical oxygen and feels the need to use only aviator's oxygen, please pass the information on. > > > > Again, Your local supplier could solve all of the questions and even provide you with a copy of the necessary paperwork should you so desire. > > > > I get the impression that some people are preparing to do their own mixing. Especially after hearing Cobb's report on the trimix site. If you are just getting started with the helium thing I would spend the time to get it right and continue to ask question of the list. > > > > Jim, I'm not sure how far you want to take the web site, but it may help some if the various UN codes were supplied along with the corresponding "quality" of each. Perhaps even a summary of opinions on which is better and why. Just a thought. If I can help by providing any info just let me know. > > > > Jon Guizar > > Jon > I too have been purchasing gas for several years from the local welding > gas supply house. What you say is correct re the quality and the > suitability for diving apps. The problem with the medical grade gases > is that in some states you need a prescription to purchase and or > dispense them. Also, there may be some obscure Federal statutes and > OSHA rules which prohibit the dispensing of "medical grade" gases > without a license etc. etc. > Per my supplier, the BIG difference in the grades of these gasses is the > condition of the bottle. The older (therefore rustier) bottles become > the welding grade bottles. Also, the welding grade bottles are not > purged the same way and therefore the potential for contaminants being > introduced by the previous user of the bottle exists. Essentially, the > quality control is the big difference. > Joe > Jon Guizar wrote: > > There are regs against trans-filling medical oxygen. What they don't know won't hurt them. Besides, if you only fill your own bottles, who would complain? > > I understand the bit about needing a prescription. Hey, have you heard that DAN recently pushed legislation that allows you to purchase medical Oxygen without a prescription if the customer states it is being used for "emergency" purposes? I believe it was in the last issue of Alert Diver. Was that federal, or State? > > You are also correct about the "control" procedures being different. The O2 comes from the same place through the same fill whip and at the same time. The difference is that medical cylinders are "evacuated" prior to the fill while the industrial oxygen cylinders are not. I have watched the entire process at the local shop several times. > > The one that worries me is the "old cylinder" thing that you had mentioned. Any cylinder used for medical should also be compatible with industrial and visa versa. Not sure what they meant when they told you that. Rust and oxygen bottles do not mix. Regardless of the grade of o2. > > Sounds like they were just trying to get the point across. One thing I have found here after many conversations and watching the procedure is that very few people actually know much about what they are doing. They are shown how to hook the hoses, and turn the knobs. To make sure they don't forget or try to take shortcuts, the boss throws in a few tales that then get passed on to the customers. > > I don't trust anyone anymore with my cylinders. The last little "E" bottle I sent out for hydro came back with a fresh stamp, sticker, and fill. I was hesitant about there "drying" procedures so I drained the tank and opened it up. There was a "Ton" of flash-rust in this thing. It was sickening. I put a few chips in the tank and rolled it on the floor. You should have seen the rust that came out of this tank. > > I tumbled the inside to a "glassy" finish and properly dried the thing. No longer will I trade my empty bottle for one of their full bottles. I fill it myself at home or I stand at the shop and wait for my tank to be filled. > > Rust of any kind is just Asking For Trouble. > > Later, > > Jon Guizar > --------------------------------------------------------------- > > Part 1.2 Type: application/ms-tnef > Encoding: base64 Jon- The reference to the rust was courtesy of the fact that I was told that unless there was a specific reason for them to do so, NOBODY ever inspects the industrial grade bottles unless they need hydro (10 YEARS!) or some sort of repair (valve etc.). In the case of 02, I would think if a bottle were emptied to zero and left, time would encourage rust. I also know that what I consider acceptable condition for a bottle and what is typically done in the real world are totally different. Several years ago I had a similar experience with tanks and tumbling. I sent a set of tanks for hydro and a tumble for good measure because I had seen a few minor spots that I wanted to take care of before the bacame a problem. I was assured that the tanks were diveable as they were returned with the manifold installed. Being somewhat neurotic about this stuff I opened them anyway. They were coated with the residue from the tumbling media and were worse than when I sent them in. As a general statement, I trust VERY FEW shops with this type of stuff and prefer to to the inspections myself (and I'm not in the business) rather than trust it to a stranger. Joe -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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