HP 120

[Scraps]

Like others here, I'm a big guy (6'4", 230) who bought a pair of steel 120's when I was still an air hog.

I still use them on occasion on deeper dives (deep, as in still within recreational limits) because I like having extra air for me or others, but they are unwieldy. Just because I can climb out of the water with them doesn't mean I enjoy the experience.

So now I usually use my steel 80's because they are compact and easier to move with on a pitching deck and because I'm no longer the guy whose air consumption is the reason dives end early.

 

[UTscuba]

At least post accurate information, it is not a weird metallurgical issue, it is known sustained load cracking it is a metallurgical phenomenon that is well known, most notably in AL6351 cylinders. Further, the phenomena can be tested for using an eddy current test.

and I believe specifically Luxfer tanks fabricated pre 1988

Dates when Luxfer changed its aluminum alloy from 6351 to 6061

or did this occur with other manufacturers too?

 

[formernuke]

but they are unwieldy. Just because I can climb out of the water with them doesn't mean I enjoy the experience.

Likewise I also dont like the way they dive compared to 100's.

 

[Scared Silly]

and I believe specifically Luxfer tanks fabricated pre 1988

Dates when Luxfer changed its aluminum alloy from 6351 to 6061

or did this occur with other manufacturers too?

Yes .. Is my cylinder made from the "bad" alloy aka AL6351?

 

[Bob DBF]

I like my MP 120 Fabers, but mostly when I am going deep or working where I need the air. I dive wet, so staying in the water shallow with that much air will get cold, and I have other tanks that are smaller and lighter, both weight and buoyancy to use.

They were second hand and reasonable so no problem there. I’m 6’ 220# and have no problem with the tank, other than I wouldn’t want to do a long hike with it, although I have.

 

[rjack321]

and I believe specifically Luxfer tanks fabricated pre 1988

Dates when Luxfer changed its aluminum alloy from 6351 to 6061

or did this occur with other manufacturers too?

The other manufacturers who used 6351 aluminum like Walter Kidde let their special permits expire.

The 120 discussed here isnt even an aluminum tank

 

[Still Kicking]

I have a bunch of tanks but I use HP 120s almost exclusively these days. I dive off my own boat and it's much easier to put a couple of 120s on the boat and make 2-3 dives per tank (or a really long dive if the mood takes me) rather than to stow 3-4 smaller tanks and use one per dive.

Beach diving is generally my main fitness program (I have had to supplement that during Covid) and carrying more weight makes for a better workout

 

[Skoock]

Here is the tank. It's been galvanized and then painted over(I think?) So it's a bit hard to read.
Tank is 32" from bottom of boot to top of the valve. Im happy with the purchase and I think it'll be a great addition to the arsenal for the time being!

For comparison here's my 119, short and fat vs tall and skinny. They both have different amounts of air in them but weights seem very similar.

Thank you all for the great information and tips! Hopefully I'll be experienced enough in the future to help someone else out to pay it forward.
Cheers

 

[-JD-]

If I'm seeing it right, the exemption number matches my tanks (distributed by Genesis, made by PST). I believe the paint is a factory or distributor variant added over the hot-dipped-galvanization. I have 2 red 100s with the big Genesis 100 stickers applied over the paint.

Enjoy!

 

[Still Kicking]

Exemption is 9791 made by Pressed Steel.

Only downside to these E9791 3500 tanks (opposed to the 9791-3442 psi series) is they are DIN only but if you have a DIN reg it's not really an issue. If you loan it to someone just make sure they are DIN friendly too.