Carbon Fiber Tanks...revisited

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marsh9077

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I have a friends that uses some 3L carbons. He has never had any problems with O2. Its the exact same as steel or AL you fill it and hook it up to your unit. Nothing wrong with carbon tanks and nothing wrong with using them for O2 just as long as they are o2 combatable its not like this is some new fancy technology, other industries have been using these for years. Look at the fire/rescue/medical industry or look at the paintball industry I think this is the largest seller of personal use carbon tanks of any other industry.

Check online you can find all kinds of info on them. Luxfer has a nice PDF document on them https://www.luxfercylinders.com/img/rm_img/blog_img/454/attachments/1/luxcompinspectmanual.pdf
 

tbone1004

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please do not use these in the ocean... These are not rated for use when immersed and any microfractures in the composite can absorb water and anything not water will remain. If these are salt crystals, they will cause the carbon fibers to fail. I have patents on these things, please do not use them in the water for any length of time unless you have access to the VERY expensive equipment required to test them.
 

rjack321

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I have a friends that uses some 3L carbons. He has never had any problems with O2. Its the exact same as steel or AL you fill it and hook it up to your unit. Nothing wrong with carbon tanks and nothing wrong with using them for O2 just as long as they are o2 combatable its not like this is some new fancy technology, other industries have been using these for years. Look at the fire/rescue/medical industry or look at the paintball industry I think this is the largest seller of personal use carbon tanks of any other industry.

Check online you can find all kinds of info on them. Luxfer has a nice PDF document on them https://www.luxfercylinders.com/img/rm_img/blog_img/454/attachments/1/luxcompinspectmanual.pdf

None of these CF cylinders are rated for immersion. If water penetrates between the aluminum liner and the CF wrap the cylinder will fail. From page 7 of the cited pdf:

"These cylinders are designed and tested in accordance with the “Basic Requirements for Fully Wrapped Carbon-Fiber Reinforced Aluminum Lined Cylinders” (DOT-CFFC). The products are authorized for the transportation of compressed gases named in the permit. Cylinders manufactured under DOT Special Permit may not be used for underwater breathing purposes."

please do not use these in the ocean... These are not rated for use when immersed and any microfractures in the composite can absorb water and anything not water will remain. If these are salt crystals, they will cause the carbon fibers to fail. I have patents on these things, please do not use them in the water for any length of time unless you have access to the VERY expensive equipment required to test them.



I have some 1L and some 9L CF tanks for sump diving. The 1L are suit gas, the 9L are bailouts. I treat them as semi disposable. After about 3 years in the trash they go for exactly this reason - and I am using them in freshwater, and only a few dives a year.

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.
Just use an AL13 instead of the 2L steel.
 

rjack321

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Another lighter option is a low pressure AL8

4lbs vs 6lbs for the AL13 or 6.6 lbs for the 2L steel.
The AL8 is also pretty buoyant +1.5 full, +2 empty

Just be sure nobody goes filling it to 3K. They are thin walled like medical O2 bottles and the AL14 of yesteryear, 2015psi.
Aluminum 8 Cylinder, Orange

I have sometimes used an AL6 as an O2 bottle with the sidewinder, but unless its a very level profile I don't like it. Any significant sawtoothing with any normoxic dil (even air) will deplete that 6 fast. Its fun to dive for short dives with minimal sawtoothing though.

Kiss also sells a short fat Catalina 14. Its standard on the Kiss Spirit, I don't know any other scuba vendor selling this as it was not originally marketed as a scuba cylinder. But you could get one from Kiss.
 

marsh9077

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None of these CF cylinders are rated for immersion. If water penetrates between the aluminum liner and the CF wrap the cylinder will fail. From page 7 of the cited pdf:

"These cylinders are designed and tested in accordance with the “Basic Requirements for Fully Wrapped Carbon-Fiber Reinforced Aluminum Lined Cylinders” (DOT-CFFC). The products are authorized for the transportation of compressed gases named in the permit. Cylinders manufactured under DOT Special Permit may not be used for underwater breathing purposes."





I have some 1L and some 9L CF tanks for sump diving. The 1L are suit gas, the 9L are bailouts. I treat them as semi disposable. After about 3 years in the trash they go for exactly this reason - and I am using them in freshwater, and only a few dives a year.


Just use an AL13 instead of the 2L steel.

Wow very interesting, I had no idea thanks for posting this info. I have never had any interested in CF tanks for diving and know very little about them I just happened to own 3 of them for paintball and I know my friends has a set for his unit and he just fills them like normal and dives them like normal tanks. I just assumed they were fine to use for diving since I have seen him do it and I have seen that Luxfer makes them. I will for sure have tell him about this, funny thing is he is a TDI instructor so you would think he would know better but... He is Chinese (and I do not mean this in a racist way or have anything against Chinese) and I know he bought them in Hong Kong and just from all my time spent in Asia and I have spent a lot of time in China for work I have seen that sometimes different standards are applied there, corners are cut, and things are sold just to make money (once again not trying to be rude, or have anything against the Chinese and I rally hope I am not offending anyone). I will be seeing him in a couple months I am for sure going to take a look at them and see what brand they are etc
 

rjack321

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I bought my sump diving carbon fibers from Alibaba myself. They are not approved in this country and I can't get them tested either.

Supposedly some last longer than others and some dry-ish caver guy in Aus has actually tried to figure out which Chinese sources are better than others. He contacted me on the book of face awhile ago but never told me which vendors were better vs worse in terms of in-water degradation rates. Its safe to say that carbon fibers are a niche tank.
 
https://www.shearwater.com/products/swift/

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