How can I prevent my cylinder from corroding? (Damage to paintwork)

[Scubadou]

Hi guys, my cylinder has managed to come loose whilst I was driving and ended up rolling about in the back of my car. As a result of this it has collided with other equipment and has ended up with a small amount of damage to the paintwork. Can anyone advise the best way to tidy this up cosmetically and more importantly prevent corrosion?

Thanks in advance!

 

[Scubadou]

My tins -- of which there's many as they breed -- are all treated as any piece of working equipment. They're covered in scars and don't rust and also don't fail a test as per below, picture taken 4 years ago and the flat bottom ones are still in the garage (now being used as banking gas with another couple of twinsets). The round-bottom ones were converted to sidemount and were moved on to their forever home -- and still haven't been painted.

I did once buy a pair of ancient 7's which looked awful but passed their hydro. So I painted them with some white Hammerite paint. Looked all white afterwards.

View attachment 740680

Perfect, that's settled any anxiety I had about the paint chip developing and the steel rusting, resulting in the cylinder failing a test! I'm new to diving and this is my first cylinder so I didn't know if it was a cause for concern or not. Thanks for replying to my post mate.

 

[Wibble]

Perfect, that's settled any anxiety I had about the paint chip developing and the steel rusting, resulting in the cylinder failing a test! I'm new to diving and this is my first cylinder so I didn't know if it was a cause for concern or not.

Aww, bless. Welcome to our lovely sport.

They do breed if left alone and if you get addicted to the technical side. First there's the 12 litre steel. Then there's the bottom stage. Then another 12 litre. Then a twinset... All downhill from there. Can't see the 9 smaller rebreather cylinders in this pic!

 

[Scubadou]

Aww, bless. Welcome to our lovely sport.

They do breed if left alone and if you get addicted to the technical side. First there's the 12 litre steel. Then there's the bottom stage. Then another 12 litre. Then a twinset... All downhill from there. Can't see the 9 smaller rebreather cylinders in this pic!

View attachment 740707

Thanks! I'm really enjoying it so far, and I hope they do breed - it would save me from having to buy new ones haha. Wow - it must be expensive keeping all of them in test!

 

[Wibble]

Thanks! I'm really enjoying it so far, and I hope they do breed - it would save me from having to buy new ones haha. Wow - it must be expensive keeping all of them in test!

Test? Nope, not with you

Some are, most aren't. Neither are the bailouts for that matter as they can be occasionally topped off.

 

[Scubadou]

Yeah like as in getting them tested and certified all the time must be a nightmare lol

 

[Boarderguy]

Yeah like as in getting them tested and certified all the time must be a nightmare lol

You only get the ones you need filled often tested and certified. Bail out tanks keep their gas for years until needed or just topped off from a tank that has recent tests. Pony tanks can get topped off with a HP tank unless you travel with it.

 

[Eric Sedletzky]

I’ll add to using zinc paint to brush a little right where the mark is (only if there is bare steel showing.) Zinc dust coatings are worthless over anything other than being used direct to metal (DTM). The way zinc works is it takes the hit by becoming an anode, it’s the less noble metal instead of the metal it sits on. Even though painted cold galvanized zinc coatings are not completely waterproof, they don’t have to be because the metal they are on can’t rust as long as there is enough zinc taking the galvanic corrosion, but the zinc has to be in direct contact with the metal.
The other thing you could do is use a little JB weld.
JB weld is an epoxy and it is water proof and oxygen proof. Once you cut off the source of oxygen and moisture to ferrous metals (or any metals) they can not rust or corrode. You can do a nice job by tooling the JB weld into the paint gouge so that you maintain the same contour as the surrounding paint so it’s not all globbed up.

Or just leave it and make sure you rinse it well.

The worst thing you could do would be to brush touch it with some cheap paint which water could migrate through but provides no galvanic protection like zinc does, or completely waterproofs like epoxy does.

 

[Scubadou]

I’ll add to using zinc paint to brush a little right where the mark is (only if there is bare steel showing.) Zinc dust coatings are worthless over anything other than being used direct to metal (DTM). The way zinc works is it takes the hit by becoming an anode, it’s the less noble metal instead of the metal it sits on. Even though painted cold galvanized zinc coatings are not completely waterproof, they don’t have to be because the metal they are on can’t rust as long as there is enough zinc taking the galvanic corrosion, but the zinc has to be in direct contact with the metal.
The other thing you could do is use a little JB weld.
JB weld is an epoxy and it is water proof and oxygen proof. Once you cut off the source of oxygen and moisture to ferrous metals (or any metals) they can not rust or corrode. You can do a nice job by tooling the JB weld into the paint gouge so that you maintain the same contour as the surrounding paint so it’s not all globbed up.

Or just leave it and make sure you rinse it well.

The worst thing you could do would be to brush touch it with some cheap paint which water could migrate through but provides no galvanic protection like zinc does, or completely waterproofs like epoxy does.

Thanks for the in depth reply, would covering the bare metal spot with nail polish be ok then?
If I'm correct, the nail polish is acrylic based and therefore is waterproof?
Thanks

 

[Boarderguy]

Thanks for the in depth reply, would covering the bare metal spot with nail polish be ok then?
If I'm correct, the nail polish is acrylic based and therefore is waterproof?
Thanks

Robot or human?

$6 and is what you're looking for. I've never had an issue with rust-oleum when I've prepped and cleaned the surface properly. Never used it on a tank though.

 

[Scubadou]

Robot or human?

$6 and is what you're looking for. I've never had an issue with rust-oleum when I've prepped and cleaned the surface properly. Never used it on a tank though.

Thanks for the help, I'll take a look!