Good morning,

I have to build a +- 2.5 liter CF air tank that hold 10 bars continuously.
My plan is to shape a cylinder (7.5 cm diameter and 15cm long) in a block of foam that need to resist epoxy resin under vacuum, wrap it with 6 layers of CF, after cooking I will drill two holes where I will later install some plugs, filling through them acetone to dissolve the foam and get a final clean inside piece.

My questions are :

- is my plan the easiest or do you have a better idea ?
- which foam to use (I want to avoid glue in the process and 10cm height is your only option) ?
- how many layers of 400gr CF would you recommend (my intention is 6) ?

Thanks for your kind advice.

               

This is definitely one of those projects where you will have to do extensive tests, and probably also a destructive test of at least one tank to be sure it will hold the 10 bar pressure..

I forgot to mention winding the tow on at an angle, but 45 deg. is too steep .. probably more like 10 deg ..

 I have made combination CF "tanks" for water propelled amateur rockets, that easily held 16 bar (The highest pressure the compressor would produce) ..   We made at test setup by drilling a hole in a sheet of 10 mm polycarbonate an mounting the "tank"  on one side, and keeping the testers and equipment on the other side .. We used a 160 Bar firefighters air tank to test, and the "rocket tank"  did not crack at 60 bar .. at which point we stopped .. any higher pressure would have made the tank a rather  too potent "cracker" --   
I was not worried by danger from the shards from the tank, but rather the metal fittings at either end ..

These "tanks" were made from a thin (0.6 mm) alu cylinder with a rocket nozzle at one end and a cone at the other .. Both were held in place by the CF wound on the outside.

Combined thickness was about 4 mm !!!    the outer layer was a kevlar braided hose .. 
Toray T700 12K Tow was used to wind on ... directly on the aluminium ..

So ... it can be done ... but at ones own risk, and it takes a lot of experimenting ..
Just sorting out the bonding in of the connectors is a job in it self ---

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Thanks for your inputs. I will start testing in one week when the 25mm CF spread tow ribbon will be received.
My main concern is indeed about the inserts as I only have the oem ones so it should be perhaps a good idea to get some spares first. I will keep you posted if anything showable.

Do you know who is building that kind of thin 0.6mm alu cylinders as I need some for other tanks containing hot oil under pressure please ?