Carbon Fiber Tanks...revisited

[v101]

It's been over 6 years since this topic was discussed on this forum.
wanted to get any feedback if divers or rebreather divers have been using carbon fiber tanks for their o2 bottles and experiences with them.

I am interested to reduce the weight of my setup thus why I am interested.

 

[Addison Snyder]

weight of my setup

Hate to run a tangent so quickly, but what kind of setup do you have that needs to shave a couple pounds so badly?

Are you looking to lose weight above water or below water?

 

[v101]

Diving a sidewinder, so I have a steel faber behind me near my bum. but heavy setup... trying to just make it a tad lighter, so I can try to reduce the counter weight a bit on my shoulder.

 

[v101]

So trying to reduce the weight above the water for when i put the harness on. i feel the weight difference will help with reducing the weight by a few lbs.
it would help a bit under-water also, i tend to have not enough lift when i haul stages with me.

 

[michael-fisch]

I use CF Tanks mounted on my Flex RB which is carried as a completely selfcontained neutrally buoyant bailout RB. In an emergency I can also easily pass it off to a buddy, since it is rigged as a stage.

Michael

 

[v101]

no negative issues with it, or observed issues using it underwater? what brand CF tank do you use ?

Im considering using a 2.17L CF tank weight wise it will be over 3 lbs lighter, which will help w/ a bit of weight reduction.

 

[michael-fisch]

I bought 4x Armotech HP-Flasche, PI, 1,5l, 300Bar back in 2015 off Amazon.de.
These are sold as generic 1.5L 300Bar paintball tanks and I paid 189 Euros each back then.
Mounted them on 2 homemade 316Ti rails attached to the Flex RB (1 in use and a spare set for another dive)
Had to add around 450grams of weight to the lowest end (Butt) of the Flex in order to make it neutrally buoyant with a half full counterlung in freshwater using Nautec Valves and SP MK17 regs.
If you want, I can take a couple of pictures late this afternoon and post them this evening
Basic specs:
MCCR, Petrel 2 Computer, 16" Cooper hoses, Golem Gear DSV, double button MAV, and an extra fitting on the 2nd stage to connect external tanks.

Michael

 

[grantctobin]

I bought 4x Armotech HP-Flasche, PI, 1,5l, 300Bar back in 2015 off Amazon.de.
These are sold as generic 1.5L 300Bar paintball tanks and I paid 189 Euros each back then.
Mounted them on 2 homemade 316Ti rails attached to the Flex RB (1 in use and a spare set for another dive)
Had to add around 450grams of weight to the lowest end (Butt) of the Flex in order to make it neutrally buoyant with a half full counterlung in freshwater using Nautec Valves and SP MK17 regs.
If you want, I can take a couple of pictures late this afternoon and post them this evening
Basic specs:
MCCR, Petrel 2 Computer, 16" Cooper hoses, Golem Gear DSV, double button MAV, and an extra fitting on the 2nd stage to connect external tanks.

Michael

Picture would be awesome. RJack uses a carbon fiber bottle for his suit gas. The ones Sotis distributed either weren’t legal or weren’t eligible for hydro. All fun and games until you get a chip in the gloss and some water intrusion.

 

[michael-fisch]

1.5L Stainless steel core, 986gr weight.
If you can find them and get the special valves they need made up, filling them shouldn't be a problem since you'll already have your own compressor and a source for 300bar O2. Don't expect to find a dive shop that can or wants to fill them, it's a lot of work to pump 26cuft of gas or O2.
RB diving, when you get to the point of having a bailout RB is not a cheap hobby. I currently have a climate controlled double garage full of dive gear n tools with the car parked outside in front.

Michael

 

[Diving Dubai]

It's important with Carbon cylinders that the user is aware that they are "uninspectable" and easily damaged

For those not familiar with the construction, its a thine metallic liner wrapped in Carbon for strength which in turn is wrapped in glass fibre which is there solely for abrasion resistance.

While you can inspect the ID of the liner you can't (easily) inspect the OD with its interface with the carbon. Why is this important? Should moisture penetrate the glass layer (highest risk area is the neck, then galvanic corrosion will set in. Both Stainless and Aluminum are very susceptible to this. It was a constant struggle on Aircraft components

It is possible to inspect the OD of the liner, but you need either to X-Ray it, or use an Ultrasonic inspection. Both are quite tricky, and require sensitive equipment and significant expertise (as opposed say to weld inspection on pipes)

I helped develop and write a procedure to inspect carbon fire fighter cylinders, and for the most part it was cost prohibitive unless you had a sizable quantity to inspect


Just something to bear in mind