N/A Painting a PCP tank?

[Motorhead]

Done painted too ... Tho on Aluminum where some scuff prior to paint can be done. Not so sure I would be comfortable scratching up an CF wrap bottle for painting

 

[Ricklin]

Lightly scuffing the clear coat will do no damage and your paint will adhere. I would not do that as I prefer seeing the CF tho a ding or deep nick should be visible.
Can sure see by the posted cut up bottles that Alu. liner is relatively thin, yes it looks pretty husky until the pressure is considered. The reason the SCBA bottles are clear coated is the ability to inspect the exterior for damage to the CF itself. I Iike my survival suit bottle sleeve a lot. The bright red color is good too.

 

[Bernie7]

I'll wager that the main strength of CF tanks come mainly from the alloy and most of the tanks supplied only have a minimal layer of CF over the top which will give extra strength, but I doubt they rely on that, and looking at most tanks the transfers that have been applied will have to have something over them and I would be surprised if it wasn't just a coat of 2K clear or matt.

The aluminum inside is a liner to ensure it’s “airtight”. I’ll try to hunt down the reference documentation but this point has been raised multiple times before. Going off memory, the ‘strength’ does come from the CF wrapping. It’d be interesting to chop a 3k AL tank and have it side by side with the one in the image above.

 

[Aunsell]

The aluminum inside is a liner to ensure it’s “airtight”. I’ll try to hunt down the reference documentation but this point has been raised multiple times before. Going off memory, the ‘strength’ does come from the CF wrapping. It’d be interesting to chop a 3k AL tank and have it side by side with the one in the image above.

I’m sure the carbon fiber adds some amount of strength as well as protecting the aluminum from denting

 

[bchannell]

Hydro testing is not destructive testing. Destructive would be pressurizing the cyl until it failed. Understanding fatigue and resiliance is a complicated science.
The short answer is that even hydro testing doest come close to the permanent damage pressure. It does contribute to cycles (fill/empty) but no more so than regular use. Ever notice the REE spec on cylinders. As long as it doesn't expand past that spec, usually measured in cc of water expansion, then all is well. 4500 cf cyls are usually hydro d at 7500, which is still less than half their burst.

 

[Aunsell]

Hydro testing is not destructive testing. Destructive would be pressurizing the cyl until it failed. Understanding fatigue and resiliance is a complicated science.
The short answer is that even hydro testing doest come close to the permanent damage pressure. It does contribute to cycles (fill/empty) but no more so than regular use. Ever notice the REE spec on cylinders. As long as it doesn't expand past that spec, usually measured in cc of water expansion, then all is well. 4500 cf cyls are usually hydro d at 7500, which is still less than half their burst.

So what you’re saying is the burst pressure is a long long way off from 4500psi

 

[Ricklin]

I'm mainly cautious of where I place my paws on the bottles, and handling them for filling. Keep hands away from the bottle neck, period. My research indicates cylinder burst is highly unlikely, you want your hand no where near a burst disc letting go. Same goes if the O-ring might extrude out the neck of the bottle where the valve screws in. 4500 will cruise right through your paw. Do not have it there in the first place. Handle your high pressure air bottles in such a way that your chances of injury are minimized, that's very sudden leaks by far the most likely failure. Not bottle ruptures and flying CF.

 

[jmohme]

The epoxy resin in the CF tank should be fine for any type of paint you can buy including automotive. What I am not sure about would be the clear coat over the tank. Epoxy paints are not UV resistant thus they typically use a clear urethane or lacquer to protect from UV radiation. They may not do this on airgun tanks thinking they won't be in the sun long. Anyway I would use a polyurethane paint along with a catalyzed clear. Though in reality any rattle can paint would work just not as durable.

You are probably correct, but at 4500psi, the words "Should be" rate right up there with "Should have".
Paint it and probalby never have a problem, but I will just leave mine as it is. I am not entering my gun in a beauty contest.

 

[Ricklin]

We are repurposing a highly engineered product. The manufacturer has good reason to use clear coating. The clear coating permits exterior visual inspection of the reinforcing fibers that give these thin aluminum bottles their strength. Consider a fabric removable cover rather than paint to permit that important visual inspection. The clear coating allows a very good view of the underlying filaments.