Extended my committment - and question about hydro

[nuderdiver]

Well, I extended my scuba commitment today by another $816 today, for two HP steel 100 tanks (filled with EAN-32 and with sticker). Given the amount I dive, it makes no sense at a financial level (cost to rent is only $3 more than the cost to fill your own) - I did it for the convenience - going to the LDS when I want to get air, instead of always having to go back right away to return rental tanks. Hopefully it wasn't a big mistake.

Also had to spend $25 to get my pony bottle a visual inspection - not a very satisfying way to spend $25, that's for sure.

All of this got me thinking about hydro tests. What is the typical cause of a tank failing? Does it just get stress fractures from the pressure, or designed to fail, or hidden defects, or random chance, or what? Is it a small chance they fail - can you expect them to last a LOOOOOOOONG time if they are not abused or what? For this question, I'm talking specially about HP steel 100 tanks.

 

[halocline]

There are two things off the top of my head that could cause your HP100s to fail hydro, abuse (like a wet fill, corrosion, etc...) and poor testing technique by the hydro tester. If your tank is one of the galvanized SP (Special permit) tanks (3442 PSI) there have been reports of those occasionally (not often) failing the first hydro. It's thought that the testers in those cases did not 'pre stretch' the tank by first pressurizing them to 90% of test value as was dictated by PST, one of the early manufacturers of those tanks. I believe I have read about this happening to a few worthingtons, and worthington replacing the tanks in question. So assuming you bought them new from a dealer you should be covered. But, choose your tester carefully. If you have the faber FX series, I've never heard of those failing hydro; mine passed easily on its first.

Nobody really knows what the life span of the SP tanks because they have not been around for several decades. The 3AA tanks, aka LP steels, easily last 50 years (or much longer) with moderate care. It wouldn't surprise me to see the SP tanks enjoy a similarly long life.

You'll love having your own tanks, and I imagine you're diving in a drysuit up there so if you've been renting AL tanks, you're in for a real treat.

$25 for a vis on a pony is a bit of a bend-over-and-spread-'em price, especially when you bought 2 new steel tanks presumably from the same shop. But, I imagine there's not a huge selection of dive shops up there. With service like that, maybe they will be one less.....

 

[akdeepdiver]

In my hydro shop, we typically see steel tanks fail for one reason, excessive corrosion that weakens the cylinder wall due to pitting. We catch this due to the pre hyro visual inspection we do. Occaionally (rarely) one sees a tank fail due to excessive overexpanson, and yes, we do the round out test. Even with the test, failures do accasionally happen.

 

[ajtoady]

Nuder I have to agree with halocline, $25 for a vis seems a bit much. I just had two of my steel hp 117's vis'd and paid for 4 air fills. The smallest of my tanks are the 117's, so I get large fills. Total cost was $36 and included the new valve-tank vitron O-rings. When I bought my two hp 117's they were $800 with taxes, filled, and stickered. I also enjoyed free fills for 6 months. That kind of treatment is why I patronize my LDS when I can.

ps. you'll love steel tanks after diving aluminum.

 

[nuderdiver]

There are two things off the top of my head that could cause your HP100s to fail hydro....

Well, that's good to know. Thanks

If your tank is one of the galvanized SP (Special permit) tanks (3442 PSI)...

Dunno. But they were factory hydroed in Jan 11. Could they be the SP tanks?

You'll love having your own tanks, and I imagine you're diving in a drysuit up there so if you've been renting AL tanks, you're in for a real treat.

I always rent steel tanks locally, specifically for the "treat" you're alluding to

$25 for a vis on a pony is a bit of a bend-over-and-spread-'em price, especially when you bought 2 new steel tanks presumably from the same shop.

Thought so - and yeah, I did buy the tanks from the same shop. I took in the pony when I went in to check out the tanks (I'll pick them up today). Ah well - live and learn I guess.

But, I imagine there's not a huge selection of dive shops up there. With service like that, maybe they will be one less.....

Well, we have 3 here in town.

Nuder I have to agree with halocline, $25 for a vis seems a bit much. I just had two of my steel hp 117's vis'd and paid for 4 air fills. The smallest of my tanks are the 117's, so I get large fills. Total cost was $36 and included the new valve-tank vitron O-rings.

That's a good deal. 4 air fills here along would cost you about $48.

When I bought my two hp 117's they were $800 with taxes, filled, and stickered. I also enjoyed free fills for 6 months. That kind of treatment is why I patronize my LDS when I can.

No such luck here. I'm horrible at negotiating this kind of stuff.

ps. you'll love steel tanks after diving aluminum.

Yeah, I only get stuck with Al tanks when I travel somewhere else. I hope I can find a dive operator in belize that uses steel tanks.

 

[TSandM]

Steel tanks, well cared for, can last a LONG time . . . we have two in service that date to the 1970s. You will be happy you have tanks. It makes diving MUCH more convenient.

 

[Brandon]

Funny to hear non-Alaskans commenting on the high costs at our dive shops... you should see what we pay for a tomato!

I was thinking that $816 for a pair of HP100s was actually a pretty good price. They go for what, about $350 online, then add another $80 for shipping to Alaska (USPS)?

Enjoy the new toys,

-B

 

[Nwcid]

I feel your pain. We just bought 2 new HP 100's as well for the same basic reasons. Ours were a few $$ cheeper but I am in WA. I did it for the same reasons you talk of. Where I am at there is no LDS so renting tanks would be a 150 mile/4hr round trip and that does not work.

One nice thing here is that we have a local dive team with a compressor. Join the dive team and get free air.

 

[Bubbletrubble]

Why don't you just purchase a transfill whip so that you can fill your own pony tank from one of your larger capacity tanks?
$25 for the annual vis on your pony is too much.