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From: ScottBonis@ao*.co*
Date: Tue, 4 Jun 2002 04:25:44 EDT
Subject: Re: Nitrox Sticker
To: Bakalite@ba*.co*, richgulley@qw*.ne*, NRadov@ax*.co*,
     techdiver@aquanaut.com
Hi Paul,

You say << The whole "oxygen clean" thing revolves mainly around 2
points, 
lube 
and o-rings.  As far as lube is concerned, almost everybody is using 
the O2 safe stuff anyway, because it's a much better lubricant. >>

From the first part of your statement, could you please explain a little 
further about what the o-rings (as opposed to the lube) have to do with 
"oxygen clean".  Do you understand the difference between "oxygen clean" and 
"oxygen compatable?"

And from the second part of your statement, the politest thing I can think of 
to say is STFD and STFU.  Even though you choose to offer advice on this 
list, you obviously don't have even the slightest inkling of what you are 
talking about.  Would you care to accompany me to the repair area of any ten 
or twenty randomly selected scuba shops?  Do you really think you are going 
to see oxygen compatable lube as opposed to silicone grease being used on 
regs?  Get real.

You also say later<< Of course I'm just a diver who's read some books and 
looked up some stuff on line, I'm no authority on the subject. >>

Boy, is that true.

Take care and dive safe,       Scott

Some weeks it's just not worth the effort to gnaw through the restraints and 
scramble up out of the pit.




In a message dated 6/3/02 6:55:00 PM, Bakalite@ba*.co* writes:
<< Rich Gulley wrote:
~
>  > I think you missed my point. Let's try this again from the top. All tanks
>>  always need to be completely clean, and obviously that means we should
>only
>>  fill from known clean gas sources. I didn't mean to imply that you don't
>do
>>  this. If it makes you feel good to follow some sort of extra oxygen
>>  cleaning ritual and slap a sticker on it then go ahead, but it doesn't
>>  change what is actually in the tank.
>
>I agree, but what do you mean by "extra oxygen cleaning ritual"? A tank is
>either clean and rated for oxygen service or not.

The whole "oxygen clean" thing revolves mainly around 2 points, lube 
and o-rings.  As far as lube is concerned, almost everybody is using 
the O2 safe stuff anyway, because it's a much better lubricant. 
O-rings are really not an issue.  The "o2 safe" part of O-rings 
doesn't really refer to them causing a problem in terms of 
combustion, but rather that some materials will degrade faster in an 
oxygen environment than others.  Regular O-rings seem to work just 
fine, and since we replace them all once a year anyway, it's really 
not that big a deal.

There are two other issues, which really don't affect mots people. 
One is that some dry sealed systems use a whole bunch of lube in the 
dry chamber, and people have been using silicone for that.  My regs 
are Apeks, which don't need that, so I know little about this.  The 
other is that certain metals are more combustible, such as titanium. 
Don't use regs that have titanium parts (they'll tell you on the box, 
because titanium is really expensive and "sexy" .... and dangerous). 
Some Apeks regs have titanium parts.

In reality, very very few tank explosions happen, and I'm sure a lot 
of "dirty" tanks get filled all the time.  Usually, the tank 
explosions have nothing to do with oxygen at all.  There was one 
recently where the tank was rusted through, and the shop owner filled 
it even though it was well out of visual and hydro.  He died.  There 
is another one that is easily found on the net, which was apparently 
caused by cracks in the material.  Some years ago a bunch of Catalina 
tanks were manufactured with an alloy that has since been shown to be 
somewhat less stable than you'd want.  Some of those tanks develop 
cracks in the neck and then explode when filled.  Newer tanks aren't 
made with that alloy, but all the AL tanks are tested using the 
Visual Plus system anyway, just to make sure.

All the oxygen fires that I'm aware of are related to boosting the 
oxygen, except for the one in San Diego, where the guy was using a 
titanium regulator.

Of course I'm just a diver who's read some books and looked up some 
stuff on line, I'm no authority on the subject.

>I have read what Trey has said. I also think he has more practical knowledge
>on this and any other diving related matter. I fallow his advice, it is
>beyond sound. But I don't remember him saying to do something easier just
>because you can get away with it.

I think Trey says basically that putting a sticker on a tank is 
dangerous, because you are now making assumptions about it's 
cleanliness, or the contents, and the sticker doesn't prove anything. 
It basically provides a false sense of security.

-Paul B. >>
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