Been out of the loop for 4 years what is the situation with Carbon Fiber Tanks?

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Julius SCHMIDT

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I have fibre wrapped aluminium tanks is this what you're talking about
 

Degenerate

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I’m still unclear how the EU (which leans towards being a ‘nanny’ state) allows 300 bar tanks. One of life’s mysteries

Not a mystery at all, it's not like 300 bar tanks are ticking time bombs.

Got a mate who works as a firefighter and I've had the chance to play around with their carbon fiber tanks a bit, they are so light that strapping them on your back and going diving would be like bringing a life jacket basically, extremely buoyant.
Completely useless for regular diving IMO, although I know some (very few) people on this side of the pond use them for rebreathers, for some reason...
 

broncobowsher

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Rebreathers are one place where there can sometimes be a purpose to it. Some are rather heavy, and in cold water that is fine. Go someplace warm, now they are negative. Go carbon fiber to try and get them more neutral. It can also be a travel thing, again weight, trying to not be overweight on luggage. But you really have to know your destination and if you can get your exotic tanks filled when you get there. Even then you are probably only getting a 200 bar fill, not 300. Not extra capacity, just less weight.
 
OP
Robbyg

Robbyg

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I can’t imagine why anyone would want those big carbon balloons floating around even if they WERE practical. In other domains everything is judged on a ‘per weight’ basis, every gram of excess material is painstakingly shaved off or substituted with unobtanium to produce the leanest and meanest possible product. Scuba is the exception to that rule, especially in cold water. I don’t even like aluminum tanks: too light!
Anyone know how they’re hydro tested? The point of hydro is to stretch the metal just a little bit and observe how well it recovers. Carbon fiber is brittle though, any stretch is too much stretch for it...
They Hydro test them the same way they test regular tanks. Only difference is that they use 7500 PSI at full pressure testing. Everything else I can see looks the same. I am sure the amount of water displaced is different but its the same type of setup.
 

tbone1004

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The hydro for carbon tanks is basically useless. It's done obviously, but it doesn't tell you anything since the composite doesn't move at 7500psi if it structurally sound. Basically any expansion means that the matrix has failed.
What the hydro won't do is show you micro cracks in the composite itself which is where intrusion occurs. Intrusion of salt water leads to salt crystals drying inside of the matrix. Once dry, any flexing of the matrix causes the salt crystals to "pop" individual carbon filaments and will lead to eventual failure. This is why they are not rated for submersion.
I have done design work on these things, it's not a joke. If you're using them for special sump projects, that's one thing, but they should be treated as disposable.

If you are trekking gear across paths, get a cart with offroad tires.
 

rjack321

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We just had this discussion... To avoid repeating myself here's the other thread.
Carbon Fiber Tanks...revisited | ScubaBoard

Bottom line unless you have a highly specialized application, money to burn, a non-dive shop way to fill them at home, and lastly you consider them disposable - you don't want CF tanks.
 

mac64

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I do own 4 of them and use them intead of alu 80's as bailout-tins when diving CCR.
Do you use stainless steel bands on them? What do you think of them to replace 12ltr Fabre steel side mounted
 

Magnus Lundstedt

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I’m still unclear how the EU (which leans towards being a ‘nanny’ state) allows 300 bar tanks. One of life’s mysteries
EU is no state, they have no say in my way of diving.

And becouse we used 300 Bar tanks since forever there are no way new regulations to outlaw them, without any sound reason, would ever be accepted from the different nations.
 
https://www.shearwater.com/products/peregrine/

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