DOT Expiration date on early Tanks?

[duckbill]

I thought it was possible to delete my own posts. Might be a good idea in this case. Anyone know how?

JamesBon, I was only kidding with you. Your post is fine. I don't think scuba diving is a politically charged sport with monitored forums and all....inspite of the scubanazis:cool2:

See? I'm kidding again (about scubanazis, that is)

 

[PhilEllis]

Phil,

I'm actively looking at this issue of the tank's age, as I have the set of doubles which are within 4 years of that 40 year date. They also have a current hydro from late last year. But, they may be taken out-of-service because of the information you have provided.

SeaRat

One day next week, I will try to clip the entire deliberation on this issue from the federal register. It is an interesting read and would change many minds about the safety of these cylinders with a careful and thoughtful read of the text.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[JamesBon92007]

JamesBon, I was only kidding with you. Your post is fine. I don't think scuba diving is a politically charged sport with monitored forums and all....inspite of the scubanazis:cool2:

See? I'm kidding again (about scubanazis, that is)

Well, maybe I'm paranoid but they ARE after me. I'm NOT kidding. It seems I somehow slipped through their brain-washing programs and they want me for "re-education."

I noticed on recent posts of mine there is an "Edit" button. On older posts there is not. Is there a time limit for editing one's posts?


Here's my take on the 6351 alloy tanks to far: You need to get a VIP once a year, a Hydro test every five years, and a Visual Eddy but I'm not sure how often. It supposedly takes 8-9 years for a Sustained Load Crack to develop. So, if a tank is VIPed every year, gets it's Hydro every five years, gets it's Visual Eddy whenever it's supposed to, and is not stored for years at 3000 psi, then I'm not seeing much of a risk. So far, as far as I can tell, the 40 year expiration date has not gone into effect so I assume the DOT has determined this to not be necessary. I have not yet read precisely WHAT is meant by sustained load so I am assuming they mean storing the tanks full for long periods of time. If the risk factor is something like 11 out of several million for abused, neglected tanks then I surmise it is much lower for properly-cared-for tanks.

I don't have any dillusions that everyone is ever going to agree on this issue but it would be nice if there was an industry standard rather than "one shop will fill the tanks and another won't." I think they should either be accepted or dumped.

 

[John C. Ratliff]

JamesBon92007, and Phil,

Here is my take on this issue--if there is an elevated risk that can be mitigated by taking these tanks out-of-service, I'm inclined to do so. I have 2 steel 72s, twin 45 steels, my twin 50s, and two AL 80s that I inherited from a friend who frequents a shop in Washington which will not touch them. I also have a set of USD triples out of this aluminum, my UDS-1 system. The UDS-1 is currently "down" due to a filler issue, and may never be brought back, but I will probably keep them (unless I trade them for something I want more). I could do all my diving on my steel tanks without suffering at all. With each set of tanks comes expenses (minimum of about $35 to keep it visual inspected per year). This takes time and effort. Because of that expenses in time and effort, it may not be worthwhile for me to keep these simply to have them. If taking them out of service removes any risk of tank rupture, and it doesn't impact me negatively (actually gives me more money each year), allows more storage space in my limited garage, then why not? I've enjoyed these tanks for over twenty years, but I could also enjoy a set of twin, or triple, 30s or 40s out of new aluminum without detriment, and perhaps even more enjoyment with a new configuration (I've got some ideas to pursue).

SeaRat

 

[duckbill]

I ALWAYS feel a certain amount of trepidation each and every time I fill any one of my cylinders, even though I know they are well cared for. There is ALWAYS some risk involved with filling a vessel to THOUSANDS of POUNDS-per-square INCH (That's a TON OR MORE PER SQUARE INCH!!!). If I REALLY wanted to "mitigate" any risk involved, I would have to take all of my cylinders out of service. I'd also have to stop transporting them in my car which could be involved in an accident. Diving, itself, carries a risk, especially river diving in strong currents. I don't see a properly tested and inspected cylinder carrying the risk that a single river dive does. However, to be honest, I don't own even one aluminium cylinder, so I guess my thoughts on the issue are moot. Ignore me.

 

[Delta_P]

... and is not stored for years at 3000 psi, ... I have not yet read precisely WHAT is meant by sustained load so I am assuming they mean storing the tanks full for long periods of time. If the risk factor is something like 11 out of several million for abused, neglected tanks then I surmise it is much lower for properly-cared-for tanks.

What's your definition of abuse? Leaving a cylinder at working pressure for several years shouldn't qualify. This is how emergency use SCBAs spend their lives, with a bleed-down and refill every three months if procedures require it.

 

[Scared Silly]

A few years back I bought a vintage US DIVERS aluminum 80 (in near mint cosmetic condition) at a yard sale and took it in to my local dive shop to be inspected and hydroed. According to the dive shop owner, this tank was one of the first aluminum tanks made and it had a DOT expiration date stamped into it, which had expired. He therefore refused to inspect or fill it.

Figuring at that point that it was worthless as anything but a doorstop, I ended up selling it for $35 at a yard sale of my own. In retrospect, I'm kicking myself.

Not sure what you had (a guess would be a Luxfer as US Divers distributed them) but for some history:

Luxfer starting making AL cylinders under SP-6498 which then granted exemption E-6498. These cylinders are exceptable for service.

Walter Kiddie starting making AL cylinders under SP-7042 which then granted exemption E-7042. These cylinders are exceptable for service.


Norris starting making AL cylinders under SP6688. These cylinders are NO LONGER VALID for commercial service in the US as the SP has expired.

Kaiser starting making AL cylinders under SP6576. These cylinders are NO LONGER VALID for commercial service in the US as the SP has expired.



The SP-6498 and SP-7042 and some others were latter given the 3AL designation and as such could be over stamped with it.

I now return you to the dead horse AL6351 discussion.

 

[elmer fudd]

JamesBon92007, and Phil,

Here is my take on this issue--if there is an elevated risk that can be mitigated by taking these tanks out-of-service, I'm inclined to do so. I have 2 steel 72s, twin 45 steels, my twin 50s, and two AL 80s that I inherited from a friend who frequents a shop in Washington which will not touch them. I also have a set of USD triples out of this aluminum, my UDS-1 system. The UDS-1 is currently "down" due to a filler issue, and may never be brought back, but I will probably keep them (unless I trade them for something I want more). I could do all my diving on my steel tanks without suffering at all. With each set of tanks comes expenses (minimum of about $35 to keep it visual inspected per year). This takes time and effort. Because of that expenses in time and effort, it may not be worthwhile for me to keep these simply to have them. If taking them out of service removes any risk of tank rupture, and it doesn't impact me negatively (actually gives me more money each year), allows more storage space in my limited garage, then why not? I've enjoyed these tanks for over twenty years, but I could also enjoy a set of twin, or triple, 30s or 40s out of new aluminum without detriment, and perhaps even more enjoyment with a new configuration (I've got some ideas to pursue).

SeaRat

I'm inclined to agree with you. An AL80 from the 70's, 80's or 90's really doesn't have any collectible value and aluminum cylinders are pretty cheap anyway and not very optimal for diving around here. Instead of fretting about whether I can get them hydroed or filled, I'd just spend $25-$50 on a used LP72 that'll outlast me and I can get filled anywhere.

Now if someone were telling me that a vintage set of triples was no good because of a stamp, then I'd seek second and third opinions, but an AL80, meh.

 

[JamesBon92007]

I don't own even one aluminium cylinder, so I guess my thoughts on the issue are moot. Ignore me.

I have four of the blasted things. According to Scared Silly's list they are all "acceptable for service." New aluminum 80s are about $150 each at the LDS. That's $660 (tax included) to replace them. Right now I'm stuck between getting new tanks and getting the old ones hydroed and VIPed and Eddyed. That will cost about $180 for the four tanks. But if some shops won't fill them then is it worth it? If I get new aluminum tanks maybe in 20 years some shops won't fill them either. Perhaps I should go all out and get new HP steel tanks. But then they might start exploding and then where would I be? I wonder if shops that won't fill certain tanks will stll VIP them. That way I could get my own compressor and still get them VIPed and hydroed as needed.

 

[captain]

I wonder if shops that won't fill certain tanks will stll VIP them. That way I could get my own compressor and still get them VIPed and hydroed as needed.

Get LP or HP DOT 3AA spec steel tanks or 6061 aluminum AL 80's , and a compressor, do your own VIS, it's not rocket science.