Changing the tank thread

[rjack321]

Are you happy with your 5? do they hold well?

I think i will order me a new one with the correct thread.

Happy? They haven't blown up yet...

But they are in no way rated for scuba use. Water will migrate between outer carbon fiber and the aluminum liner. Which will cause them to delaminate. Salt water will accelerate this process. Will I catch them failing before they explode and kill me? I hope so. I only use mine in freshwater caves and only a few times a year.

 

[pisauron]

Happy? They haven't blown up yet...

But they are in no way rated for scuba use. Water will migrate between outer carbon fiber and the aluminum liner. Which will cause them to delaminate. Salt water will accelerate this process. Will I catch them failing before they explode and kill me? I hope so. I only use mine in freshwater caves and only a few times a year.

Interesting. Do you see the water migration happening after the dive?
Sadly i only have salt water here

 

[BoltSnap]

Interesting. Do you see the water migration happening after the dive?
Sadly i only have salt water here

Dude, Why screw around with this ticking bomb? Just get rid of this shiit and buy a legitimate scuba tank from a reputable manufacturer and save yourself the headache and the potential for a catastrophe that could kill you or kill people around you or at least blow your balls away? I can't believe that you are still trying to use this PoS.

 

[rjack321]

Interesting. Do you see the water migration happening after the dive?
Sadly i only have salt water here

It's not something you can really see. It's at the microscopic level and the main reason why carbon fiber tanks are nearly impossible to rate for underwater use. Even the (rare) wrapped tanks that are rated for scuba use have had this issue.

I assume the neck area will have the most obvious impacts. What are you using them for?

 

[pisauron]

It's not something you can really see. It's at the microscopic level and the main reason why carbon fiber tanks are nearly impossible to rate for underwater use. Even the (rare) wrapped tanks that are rated for scuba use have had this issue.

I assume the neck area will have the most obvious impacts. What are you using them for?

I haven't used them yet, i was thinking maybe they will fit as a drysuit inflating tanks. Seems they are problematic.

Dude, Why screw around with this ticking bomb? Just get rid of this shiit and buy a legitimate scuba tank from a reputable manufacturer and save yourself the headache and the potential for a catastrophe that could kill you or kill people around you or at least blow your balls away? I can't believe that you are still trying to use this PoS.

Why would you believe that? Haven't said that

 

[rjack321]

I haven't used them yet, i was thinking maybe they will fit as a drysuit inflating tanks. Seems they are problematic.

I have three of the 1L size as suit gas tanks in caves when an AL6 isn't enough volume and an AL13 won't fit on a sidemount CCR.

For drysuit use in the Mediterranean an AL6 is going to serve you much much longer and not have all the corrosion issues

 

[Tanks A Lot]

I’d like to point out that diving with composite cylinders can be a tricky business.

The main issue, as mentioned earlier, is corrosion. To be more specific, galvanic corrosion. Carbon fibres sit very high on the galvanic series, not quite as high as graphite, but still significantly higher than aluminium. It has a standard electrode potential of 0.55V, comparable to copper (Even slightly higher). Aluminium, on the other hand, sits much lower in the series, with a standard electrode potential of -1.67V, making for a terrible coupling. In this setup, carbon fibre acts as the cathode, while the aluminium liner becomes the anode, corroding rapidly if an electrolyte, such as water, connects the two. Even the cylinder valve can be effected, if the epoxy layer is not sound.

For this reason, composite cylinders require a buffer layer between the carbon fibres and the aluminium liner. This is often a glass filament epoxy layer, similar to what you see on the outermost surface. Current standards limit these buffer layers to a maximum of around 15% of the pressure load at minimum burst pressure.

Because of these risks, most manufacturers explicitly prohibit the use of their composite cylinders for diving. The only manufacturer that comes to mind with a purpose-built composite cylinder for diving is Luxfer.

That doesn’t mean they can’t be used for diving, as @rjack321 demonstrates well. But it does mean, that special care and thorough inspection are absolutely essential throughout the cylinders use.

The pictures you’ve shared are interesting because I don’t see an insulating epoxy layer between the carbon fibres. That said, pictures can be notoriously difficult to interpret when taken out of context.

 

[rjack321]

Because of these risks, most manufacturers explicitly prohibit the use of their composite cylinders for diving. The only manufacturer that comes to mind with a purpose-built composite cylinder for diving is Luxfer.

Luxfer? I thought carbondive (a worthington product line) were the only underwater approved tanks? CARBONDIVE 300 - Carbon Scuba Tanks, Diving Equipment, Worthington

 

[grantmac]

Inspiro has carbon tanks. Unsure if they are the OEM or just build the dive system around them.
I'll tell you this: they are pretty trash to dive.

 

[Tanks A Lot]

That is most interesting indeed, especially as these have a steel liner! Thanks for sharing this.

I was only aware of Luxfers S106W.