I just got these from a friend, what do all of the markings mean?
- Thread starter JCastle19
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Agreed. Catalina never used the 6351 aluminum alloy that was prone to sustained load cracking (SLC). While more and more shops seem to shy away from filling aluminum tanks at or past the 20 year old mark, with some discussion (if they don't already know) they should accept tanks made by Catalina.
-Z
Scared Silly
Contributor
The green cylinder marked with "Catalina" is keeper. All others that have SP6498 are made from AL6351. See this thread: Is my cylinder made from the "bad" alloy aka AL6351?
At this point I would recycle the SP6498 cylinders and with the proceeds buy your friend some beer.
At this point I would recycle the SP6498 cylinders and with the proceeds buy your friend some beer.
Cthippo
Contributor
The 6351 tanks can be used, but they require an eddy current inspection as well as hydro every 5 years. If you want to use them you will need to find a shop that can do the eddy current inspection. My LDS does those for an additional $25. Up to you whether it is worth it for some cheap tanks or not.
This topic has been discussed in the past ad nauseum on Scuba Board.
Yes, POTENTIALLY, you can continue to keep a cylinder made from 6351 alloy in service by having it eddy current inspected at additional cost to the hydro test and visual inspection....BUT despite incurring the additional expense and passing the eddy current inspection, hydro, and visual, one often finds that thier local dive shops still refuse to fill their 6351 cylinders due to percieved risk.
One can always fill with their own compressor...if one has one and wants to assume the risk of filling a cylinder of 6351 alloy.
So while its possible to keep one of these cylinders in service, in most cases its not worth the hassle of paying for the inspections only to find limited to no sources to have the cylinder filled. The best recommondation is to just condemn and repurpose 6351 alloy cylinders and just get over the heartache sooner than later.
-Z
SlugLife
Contributor
The green Catalina tank is good to be hydro'd. The green Catalina tank was made in 1995 as seen by "08 A 95".
All of the other tanks are much older. and I'd personally scrap them. As a basic "rule of thumb" you'll want to avoid any aluminum tank from before 1990. And no, it's not "20 or 30 years old" that's the issue, but rather what the type of aluminum used to make most scuba tanks from before 1990, which is more prone to cracking.
There are technically exceptions, and you can technically hydro tanks made of the "bad" aluminum, but it's a somewhat boring discussion, and the cost of hydro+VIP is more than those tanks are worth, and even if you do hydro/vip the tank, good luck selling them to anyone who knows anything about scuba tanks.
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As far as shop-fills, I've had a shop refuse to fill a pre-1990 tank that was made of the "good" aluminum. I also had a hydro-place do a VE (eddy current) test on it, even though VE is only supposed to be done on the "bad" (6351) aluminum.
All of the other tanks are much older. and I'd personally scrap them. As a basic "rule of thumb" you'll want to avoid any aluminum tank from before 1990. And no, it's not "20 or 30 years old" that's the issue, but rather what the type of aluminum used to make most scuba tanks from before 1990, which is more prone to cracking.
There are technically exceptions, and you can technically hydro tanks made of the "bad" aluminum, but it's a somewhat boring discussion, and the cost of hydro+VIP is more than those tanks are worth, and even if you do hydro/vip the tank, good luck selling them to anyone who knows anything about scuba tanks.
----
As far as shop-fills, I've had a shop refuse to fill a pre-1990 tank that was made of the "good" aluminum. I also had a hydro-place do a VE (eddy current) test on it, even though VE is only supposed to be done on the "bad" (6351) aluminum.
Johnoly
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For the dark curiosity amongst some of us........
Bump the valve open a whisper and tell us what the air inside smells like......
CT-Rich
Contributor
It is probably going to smell like air. The amount of chemical reactions that can occur inside a scuba tank are pretty limited. IF the O2 in the tank reacted with the AL, it would not have a smell. There shouldn't be enough moisture and organic material in the tank for anything to grow. You could probably breath that air just fine even after several years.
One of the attractions of making a scuba tank out of air is that aluminum doesn't oxidize like steel will. a microscopically thin layer of Aluminum oxide forms on the surface of AL and then stops.
dead dog
Contributor
dead dog
Contributor
Is my cylinder made from the "bad" alloy aka AL6351?
Hopefully, this thread will become a sticky as it is an attempt to help educate divers on cylinders that were made from the AL6351 alloy. Please do no add posts to this thread unless it is for factual information or corrections. I especially do not want discussions on what some dive shop...
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