AL80 Fill amount??

[O-ring]

Hey O-Ring, i would like to hook up your SPG and check it against my Dive computer just for hell of it next time we are together.

We can borrow another SPG/computer from whoever else is there too so we know mine isn't the one that is off in case they come out different

 

[sheck33]

donacheson once bubbled...


In two words: That's nonsense.

nonsense indeed, ALL metals stretch and ALL metals are 'brittle' to some extent.

 

[jonnythan]

sheck33 once bubbled...



nonsense indeed, ALL metals stretch and ALL metals are 'brittle' to some extent.

To steal someone else's analogy..


Have you ever seen an aluminum spring?

 

[Bob3]

Aluminum is less elastic [under some conditions] than glass.

It's a very safe bet to say that ALL aluminum tanks will fail from repetitive stressing of fill cycles, assuming they don't die from other causes first.
Luckily the tank mfgrs get around this by engineering the critters to handle an estimated 10k cycles, something that is hard to rack up in any realistic amount of time.

Steel has no built in failure mode like aluminum.

 

[MikeFerrara]

I don't overfill al tanks. Well...maybe a tiny tiny bit. I fill slow but, if very much air is being added the temp rises enough that when they cool the fill is short. Filling in water makes a huge difference. It doesn't eliminate heating and cooling but makes a huge difference. I have prabably heard all the arguments against it but...

I don't always fill wet and in my own tanks I don't wory about a 2750 psi fill. It doesn't seem to shorten my dive that I notice. Using a single al80 may shorten my dive but being a couple hundred psi short of full doesn't.

Assuming the tank isn't filled too fast, a slightly short fill isn't because of laziness it's because of physics. If a tank is anywhere near empty it will get pretty warm even when filled slowly. It needs to sit and cool for a good long while too make re-topping effective. The main issue here is how long the customer wants to wait around and...how much it matters. In reality most will overfill a couple hundred psi and whatever it cools to is what you get. The fill may be a tad short but not bad.

 

[alpaj]

I don't think aluminium tanks are built with high pressure stress fractures in mind. But it is simply a fact of life that aluminium is more prone to high pressure stresses then steel is.

Just wondering how comon the 3300 aluminium 80's are? And how do people feel about hooking up their 3000 psi jokes to them?

 

[dherbman]

Just wondering how comon the 3300 aluminium 80's are? And how do people feel about hooking up their 3000 psi jokes to them?

My jokes are rated to 4200 psi.

As for exceeding the working pressure rating by 10%, I'd be OK with that on an infrequent basis.

 

[wedivebc]

Is this the oldest resurrected thread ever?

 

[dherbman]

Is this the oldest resurrected thread ever?

It's the dark side of doing a search.

 

[artek]

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