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Kyzzle
06-27-2009, 09:42
okay... so I am starting a new thread about this so I am not de-railing someone elses thread.

I have 2 al80 tanks that I picked up from a pawn shop last yr. I am sure they are pre-88 givin some of the other equipment that I picked up with it. But I had them hydro'd and they past. (It cost me $22/tnk at my lds)
At that time they told me about the issues with the alloys, but I never new that I may never be able get them filled... that really kinda sucks. Is that alloy number stamped on the tank? What do I look for when looking at old tanks?
Also in a previous thread, the OP who was looking at some tanks to buy, was told to ask when the origianl hydro was done... Not quite sure I understand this.... is that number stamped too? I mean I know they stamp the hydros on there but I talking about an original date.... cuz when I got my tanks back the last hydro was "scratched out" and the new hydro in its place. Make sense?

I thought since my tanks past, no matter the age, that if something was to go wrong it would during the hydro, and that I am safe to dive.... now I am concerned...

navyhmc
06-27-2009, 10:09
Best case, bring them with you to O on the 4th, we can look at them. If the VIP and hydro are current and you are sure that they were eddy current tested, they should be good to go. I know for a fact that John will fill them as he fills my circa 1982 AL 80 all the time.

The original hydro should be at the end of the second row of markings on the crown of the tank. If it's a standard Luxfer tank, it will have an arrow between the month and the year.

nrembis
06-27-2009, 10:09
any shop that scratches out an old hydro mark I wouldnt trust to begin with

JahJahwarrior
06-27-2009, 10:13
A search should answer all of those questions.

Hydros should never be scratched out, that I'm aware of, unless perhaps it was done to condemn the tank. However, if a tank were condemned, I doubt a facility would hydro it. Perhaps someone else can comment more on scratched out hydro dates, that seems odd to me.

The original hydro date as well as information pertaining to the alloy, will be stamped on the neck. Also, the manufacturer name is likely to be: Luxfer and Catalina are the main manufacturers but there are others-- find the name and post it on here. Catalina tanks are always made from 6061 and should be fine. Luxfer before mid 88 were 6351 alloy. Some were stamped 3al, some were stamped sp6498, some had other exemption numbers but 6498 is the most common.

A lot of places won't fill a 6351 alloy tank no matter what. A lot of places also won't hydro them. However, a shop which wants your money can always hydro then refuse to fill them.

It pays to do research ahead of time so you don't buy tanks you can't fill. Having purchased a 6351 tank a week after getting certified because I didn't know any better, though, I can identify.

Scuba Diving - New Jersey & Long Island New York - dive Wreck Valley - Gear & Training - Scuba Tanks & Mounting Hardware (http://njscuba.net/gear/eqpt_05_tanks.html)

navyhmc
06-27-2009, 10:18
Not filling, I can sort of understand, but not hydro? I've seen a tank have a catastrophic failure during hydro-all we heard was a light thunk. nothing damaged. In fact the we heard the noise and the tehc looked at me and said "This one failed..." sure enough, a 10" rupture just below the crown.

Kyzzle
06-27-2009, 10:39
Okay thanks...
My tanks and equipment are over at my brothers house, so I will be heading over there in a bit to look closer, cuz now I am really curious.

As far as the new hydro stamp goes, I just assumed that they scratched the old one out cuz that just what it looks like under the new stamp. But maybe they just scrape the paint away before they stamp it?? Hmm...

So just to clarify... The makers name will be stamp on there, spelled out in letter form, or is it in a number code?

Navy- I had them hydro from John.. they don't do it there they actually send it off...But I was told that they put the Eddy test to it when they hydro... is that common practice? I assumed it was on hydro's.

"Tanks" for all the help!! hehehe.....Did you see that?.....Get it?....Tanks for all the.....HaHa...ha...ha......Hoooo....

navyhmc
06-27-2009, 11:05
Okay thanks...
My tanks and equipment are over at my brothers house, so I will be heading over there in a bit to look closer, cuz now I am really curious.

As far as the new hydro stamp goes, I just assumed that they scratched the old one out cuz that just what it looks like under the new stamp. But maybe they just scrape the paint away before they stamp it?? Hmm...

So just to clarify... The makers name will be stamp on there, spelled out in letter form, or is it in a number code?

Navy- I had them hydro from John.. they don't do it there they actually send it off...But I was told that they put the Eddy test to it when they hydro... is that common practice? I assumed it was on hydro's.

"Tanks" for all the help!! hehehe.....Did you see that?.....Get it?....Tanks for all the.....HaHa...ha...ha......Hoooo....

Yeah, yeah, yeah...we give you all this information and that's the tanks we get-typical diver!!!!:smiley36:

Actually, the eddy current test is part of the VIP and since they do a VIP after the hydro, that's when it was done. I don't fully understand the eddy current test, but it's a sensitive electrical current study of the neck and the threads and if done right can show a SLC several yeras before they cracks are visible. According to Luxfer, about 2.3% of the old tanks are coming back as a fail but historically, these tanks are soewhat abused.

JahJahwarrior
06-27-2009, 13:05
Some hydro facilities say "no one will fill them, and a lot of them fail, so we don't want to waste our time doing them." I don't understand that mentality...whether or not they pass doesn't seem like it would affect the profit the firm would make from hydroing the tank...

And no, they do NOT simply re-stamp over scratched out old stamps. They might have scraped away the paint. Take a good photo and put it up here.

Manufacturer's name should be clearly spelled out in english letters. I have found some aluminum tanks that seem nameless, but that is 2 tanks out of perhaps a thousand that I've seen, filled, o2 cleaned, whatever. There will be other numbers and markings but the link I gave you explains how to read them. It's really simple, and something every competent diver should be able to do, takes less than 5 minutes to learn the basics of tank markings.

Kyzzle
06-27-2009, 14:23
Some hydro facilities say "no one will fill them, and a lot of them fail, so we don't want to waste our time doing them." I don't understand that mentality...whether or not they pass doesn't seem like it would affect the profit the firm would make from hydroing the tank...

And no, they do NOT simply re-stamp over scratched out old stamps. They might have scraped away the paint. Take a good photo and put it up here.

Manufacturer's name should be clearly spelled out in english letters. I have found some aluminum tanks that seem nameless, but that is 2 tanks out of perhaps a thousand that I've seen, filled, o2 cleaned, whatever. There will be other numbers and markings but the link I gave you explains how to read them. It's really simple, and something every competent diver should be able to do, takes less than 5 minutes to learn the basics of tank markings.

JahJah- Thanks for the link, GREAT info! I missed that link somehow when I first read your post, think I thought was your sig. line...

So I have checked my tanks... the Al 80 that I have used this whole time is a Luxfer and was manufactured in 95. SO I feel I can rest at ease on that one.
I also have another al80 in for hydro at the moment... so not sure about it... my brother took it in for me so I don't know what the stamps are on that one till I get it back.
I also have have what must be (after reading your link) an al63 ? It was givin to me by a friend who had it in his garage for years, but was told it was a 50 ? I didn't see that mentioned in the info... However I took it in last yr for hydro and past, but I have never used it yet. And there is NO manufacturer name on it. It's old.... here's the markings. And I will try to get a pic up ASAP.


3AL
DOT-SP6498-3000
R5033 USD
3^73
6-78


3^73 appears to be orig. hydro. And the 6-78 appears to be the last hydro before I had it done. So it's a 70's model.


Maybe the USD is manufacturer US diver? not sure, and I don't quite know what the other numbers mean in regards to the alloy. Maybe it should just be my first collectors piece and leave at that. My son is wanting to get into diving and we thought that would be a good size tank for him since he is on the smaller side, but knowing what I have learned now, I don't think I will chance it. Also the valve on it has two knobs... one is like a normal open and close, and the other turns and clicks and has on/off written on it...

navyhmc
06-27-2009, 16:35
It's a luxfer made on contract for USD. The valve is what's referred to as a "J" valve. The 1/4 valve with "On and off" is the reserve. When it's on, it will shut off the flow of air at around 500 psi. they usually worked from 300-700 psi as a variant. As a guess I will say it's either yellow or black, though more 63's were yellow than black.

The J-valves need to be maintained or left in the off position. Originally, the j waa preferred as the first years ofdiving, SPG's were hard to comeby and expensive-about equal to the cost of the tank. So the J was used to dignal when to go up. Not good if you needed deco though or were in a wreck. They come into their own on the doubles as it was like having 1/3 of the air in a single tank as your reserve.

cummings66
06-27-2009, 18:33
My concern reading the thread is whether or not that hydro date is gone? If you obscure any markings on a cylinder you have condemned it. That's why some shops X out a serial number or hydro date, etc. Anything that gets rid of previous data is bad.

However, that doesn't mean you couldn't get a shop to fill it because most of them don't know the rules anyhow. Plus, it's a rule not a law. So, for what it's worth it's not kosher to do it, it might or might not effect fills depending on shop and that depends on the shops viewpoint of old cylinders.

Kyzzle
06-27-2009, 18:55
After looking at it again... The old hydro wasnt stamped out or scratched out or anything. It is still there. Me being a newb looked at the new hydro stamp and saw that they scratched the paint off so they could put the new stamp on... having never had hydro's done before I automaticaly assumed that's how it was done... And we all know what happens when you Ass-u-me...

cummings66
06-27-2009, 19:15
That's better then, yes they sometimes scratch the paint off, sometimes not. If not sometimes it's not deep enough and over time it can flake leading to a hydro date that's not acceptable which is why they scratch.

JahJahwarrior
06-28-2009, 02:07
That's one of the more helpful links I've found, really helps explain how to read tank markings.

USD tanks, NavyHMC basically explained very well. That's a 6351 alloy (compared to the 6061 alloy which is safe), and I wouldn't bother hydroing it. A lot of people will fill 6351 tanks, but I personally am scared of them. I've seen pictures of what an explosion will do, and I value my life. It's an argument people will have until they are blue in the face, but I personally choose not to fill 6351 alloy tanks, even if they are eddy current tested.

The 95 cylinder is great, hopefully your second 80 turns otu to be post 89 as well!

navyhmc
06-28-2009, 03:13
In all honesty, I'm not too worried about my own tank, it's passed the hydro, VIP and eddy. From what I've read, my tank has been treated fairly gently and never dropped, left in an overly hot car, or subjected to tens of thousands of fills. I also have a lot of faith in the guy that tested it. I watched him do a few visual thread checks on tanks and he spotted cracks with a naked eye that I could barely see magnified. But still, it's unfortunate that it's lifeexpectancy is now measured in months.

JahJahwarrior
06-28-2009, 07:49
In all honesty, I'm not too worried about my own tank, it's passed the hydro, VIP and eddy. From what I've read, my tank has been treated fairly gently and never dropped, left in an overly hot car, or subjected to tens of thousands of fills. I also have a lot of faith in the guy that tested it. I watched him do a few visual thread checks on tanks and he spotted cracks with a naked eye that I could barely see magnified. But still, it's unfortunate that it's lifeexpectancy is now measured in months.

SLC is, as best as I understand it, caused entirely by sustained load and has little to do with being dropped, being left in hot or cold cars, or being filled tens of thousands of times. That's what scares me.

navyhmc
06-28-2009, 07:56
In all honesty, I'm not too worried about my own tank, it's passed the hydro, VIP and eddy. From what I've read, my tank has been treated fairly gently and never dropped, left in an overly hot car, or subjected to tens of thousands of fills. I also have a lot of faith in the guy that tested it. I watched him do a few visual thread checks on tanks and he spotted cracks with a naked eye that I could barely see magnified. But still, it's unfortunate that it's lifeexpectancy is now measured in months.

SLC is, as best as I understand it, caused entirely by sustained load and has little to do with being dropped, being left in hot or cold cars, or being filled tens of thousands of times. That's what scares me.

True to a point, I can't find the article, but something like 90% of the tanks that had SLC-not necessarily failures, but failed a vip, fell in the well used category. That and I don't keep a full tank on hand during the off season-500-700 psi to store.

acamato
06-28-2009, 22:56
I did a quick search for SP-6498 (DOT Special Permit 6498) and came up with this:

Sources - A Brief Scuba Cylinder History (http://divemar.com/NAUI/docs/sources/cylinder-history.html)
Luxfer and Walter Kidde continued production under the DOT SP6498, E6498 or SP7042. E7042 until the DOT formalized the aluminum cylinder category 3AL in July 1982

TO tell who hydro'ed your cylinder: Look at the 4 characters between the month & year of hydro. Usually a letter and 3 numbers. Look up the "approval" on this website:
PHMSA - Cylinders - Authorized DOT Cylinder Retesters: Domestic (http://www.phmsa.dot.gov/portal/site/PHMSA/menuitem.ebdc7a8a7e39f2e55cf2031050248a0c/?vgnextoid=18dee6285188e110VgnVCM1000001ecb7898RCR D&vgnextchannel=90892f5484d87110VgnVCM1000009ed07898 RCRD&vgnextfmt=print)

You can also use this website to, save some $$ and, find a local retester. The LDS will usually sends them out.

Kyzzle
06-28-2009, 23:34
Thanks Acamato for the info, good stuff!

I also went and picked up my other tank today from my Lds, which past hydro (and got a couple dives in), and after checking the "born on date"... it was made in 1991! So I feel good having two tanks with acceptable years on both my al80's... it's just the al62 that is really old, but has past hydro and eddy current... My LDS assured my that even tho it is old, if it past hydro and eddy, they don't see why I shouldn't use it. So we'll see...

Another question outa curiosity... When you all get your tanks hydro'd from your LDS, does the air fill get included with your cost of hydro, or is that extra? With my first tank I took in, it was a free air fill with the hydro, and this time they charged me extra for air... I didn't really catch it till after I left and was adding it up so I couldn't question it...

Anyways thanks to all for the help and info, much appreciated!

acamato
06-29-2009, 09:35
My LDS does not charge for air when they hydro or VIP. It is built into the price.

nrembis
06-29-2009, 11:05
I did a quick search for SP-6498 (DOT Special Permit 6498) and came up with this:

Sources - A Brief Scuba Cylinder History (http://divemar.com/NAUI/docs/sources/cylinder-history.html)
Luxfer and Walter Kidde continued production under the DOT SP6498, E6498 or SP7042. E7042 until the DOT formalized the aluminum cylinder category 3AL in July 1982

TO tell who hydro'ed your cylinder: Look at the 4 characters between the month & year of hydro. Usually a letter and 3 numbers. Look up the "approval" on this website:
PHMSA - Cylinders - Authorized DOT Cylinder Retesters: Domestic (http://www.phmsa.dot.gov/portal/site/PHMSA/menuitem.ebdc7a8a7e39f2e55cf2031050248a0c/?vgnextoid=18dee6285188e110VgnVCM1000001ecb7898RCR D&vgnextchannel=90892f5484d87110VgnVCM1000009ed07898 RCRD&vgnextfmt=print)

You can also use this website to, save some $$ and, find a local retester. The LDS will usually sends them out.


Thats a good list and is how I found the company I use in Cincinnati. I can get hydros for 2400-2640psi tanks at 12.00 and 3000psi+ tanks are 18.00, so it can save quite a bit to go straight to the source and skip the middle-man if you have several tanks.

navyhmc
06-29-2009, 14:00
With your LP tanks, did they give you the "+" testing nrembis?

nrembis
06-29-2009, 20:27
With your LP tanks, did they give you the "+" testing nrembis?

yes, I didnt ask once and didnt get it, so I make sure to have that noted on my ticket and check them before I leave from now on