Old Tank Service Help

[DivingGator]

A coworker of mine who no longer dives gave me his old tanks. I believe they were manufactured in 1986. They are Luxfer AL80's. He hasen't used them in years so they require Hydro and VIP service. I have search some past posts for info on this and this has produced many questions I was hoping someone could help me answer.

1) First of all I was reading about 6351 alloy and how potenial dangerous they are. How can I tell if these tanks were made of this material?
2) What other services might I need for these old tanks? What is tank tumbling and tank cleaning with O2? Are they the same?
3) Do they have K valve overhauls?

The tank markings are CTC/DOT-3AL3000-S80 then below P272287 Luxfer 9A86. What do these mean?

Thanks.

 

[Leadking]

1) go to http://www.luxfercylinders.com/news/releases/20041012.shtml for 6351 alloy info.

2) Why do you want to tumble (rotate the tanks with abrasive stones inside) the tanks? Have them hydro'd, VIP'd, and unless you are going to use O2 leave them alone.

3) Depends on who the valve manufacturer was-some manufacturers have either gone out of business or changed their valves. If there is an issue, buy a new valve, it won't be that much more than a rebuild.

If you need a hydro along with new valves I'd just buy new.

 

[DivingGator]

1) go to http://www.luxfercylinders.com/news/releases/20041012.shtml for 6351 alloy info.

2) Why do you want to tumble (rotate the tanks with abrasive stones inside) the tanks? Have them hydro'd, VIP'd, and unless you are going to use O2 leave them alone.

3) Depends on who the valve manufacturer was-some manufacturers have either gone out of business or changed their valves. If there is an issue, buy a new valve, it won't be that much more than a rebuild.

If you need a hydro along with new valves I'd just buy new.

Thanks for your reply. I don't want to tumble I just don't know what it is. Why would someone do this? I went to the site and I guess they used the compound until aroud 87 or 88. Save to say I guess that these tanks are made with it.

 

[mike_s]

When you got the tanks, did they hold any air or were they empty?

If they were holding air, then most likely the valves are OK. If they aren't holding air, then it's possible you'll need to replace or rebuild the valves. K valves run around $40 bucks (+/- depending on the dive shop) I'd buy a new one before I rebuilt it as the parts and labor for rebuild will cost more than $40 bucks.

If you want to see if the valves will hold air, see if your LDS will put 100psi in the tank and let the tank sit a week or two and see if it leaks out. They will prob do this w/o a hydro/visual since it's such a low PSI and not really a safey hazzard. This will give an idea if the valves will hold air. Of course they might not at 3000 psi, but this simple test will give you a good idea if they are bad or not.

A hydro will typically run you $20 to $25 bucks at most dive shops. This may or may not include a visual inspection. On average visual inspections run $5 to $15 per tanks, dpending on the dive shop.


The reason I say all this is that based on what LeadKing said, if you gotta go through all this trouble, which includes replacing the valves, you might as well buy new tanks.
$25(hydro)+$45(valve)+$10(visual) = $80 bucks on used old tanks. You can typically get a new AL80 for $120 to $130.

I did something very similar to what you did several years ago, expect I bought old tanks for $50 bucks and had to get them hydro'd, VIP'd, etc. Well, after I got them filled and went to go diving a couple weeks later, one of the tanks was empty. I thought I might have left the valve open. Got it filled again and a few weeks later it was empty again. A "water test" showed it had a small bubble leak in the valve. So had to spend $45 on a new valve. The second tank needed a new valve also a few weeks later. By the time I spent $50 bucks on the two tanks, $25 each on hydro, $10 each on Vis, $45 each on valves, extra air fills, etc, I could have bought two brand new tanks for about the same price with much less hassle.

Of course if somebody gave me two tanks, I'd prob do the same thing again. I'm a sucker for that kinds of stuff. heh.

 

[Leadking]

Thanks for your reply. I don't want to tumble I just don't know what it is. Why would someone do this? I went to the site and I guess they used the compound until aroud 87 or 88. Save to say I guess that these tanks are made with it.

The reason someone would tumble a tank is to remove corrosion inside a cylinder. Some do a minor tumble with cleaning solution to ensure no hydrocarbons (oil) are inside the cylinder. This is for 02 service because oil in high O2 partial pressure can self ignite.

 

[donooo]

I took two 6351 tanks into Luxfer and they replaced them for $50 each plus shipping. Depending on where you are, the shipping can kill you. I just happended to be traveling near the plant and dropped them off. That killed half of the shipping and they became a good deal.

adios don O

 

[Leadking]

The Luxfer rebate program ended over a year ago!

 

[Cokedude]

I had a tank given to me this spring its an oldie,,,, but it passed hydo and vip so i am in to it for $40 ,,so far no air leaks,,, I would take that chance again on a free tank lol.



Paul

 

[DivingGator]

Both tanks are still holding air at around 700 psi. I'm planing on getting them serviced this week for $35 each (Hydro & VIP).

Thanks everyone for your posts.

 

[Tom Winters]

DivingGator - if you're in Miami-Dade county, don't bother with the tanks - most of the shops will no longer touch an aluminum tank over 10 years old. 1986 sounds like you have the 6351-alloy tanks. In Broward county, at Fill Express, they will fill these tanks ONLY if they do the VIP and eddy current tests, and it is their preference not to deal with the 6351's anymore. More and more shops flat-out will not handle old aluminum tanks - whether it's fair or not has been beaten to death on numerous other postings.
So in addition to your $35 tank service, you're most likely due for a valve overhaul. Are you sure you want to spend this kind of money on 19-year old tanks that may be problematical in filling?