Small Tanks Corroding on the AP Valves BCD Commando, anybody has this too?

[ChangeAgent]

I use these with my Commando BCD as well as my wife who has one too. We are both fans of the jacket. The very first once we had started corroding very soon after we got them. Corrosion (blooming) happened mainly at the top and the bottom parts of the tanks. At the time I put it down to the tanks having been in contact with other sharp or hard items that damaged the paint and as such the aluminium started blooming.

I tried to keep it in check, but it seemed a lost battle. The second set of tanks I was very careful in how they got handled but it happened again. Again I quickly lost the battle.

The third set I got recently I got creative and put plumbing gaskets around the bottom (they are like little bumpers) and also at the neck of the tank I created protection. This did work for the bottom of the tank, and it stayed corrosion free for 36 dives. But where the letters and numbers are punched at the neck of the tank the paint just comes off and it starts corroding/blooming.

Now I talked to AP (not just this time but in the past too) and they claim they never heard of this. Which is not totally true as I reported it several times and also always send, he old tanks in to have them swopped for new ones.

My question is am I the only one who has this? Or are there others out there. I find it hard to believe that just me and my wife are the only ones where this happens. Love to hear.

 

[Edward3c]

The first question is why do you want these cylinders, most jackets now come with a direct feed from the main tank. I stopped using mine over 25 years ago. When we stopped training people how to use them, I stopped wearing mine. I didn't want someone sending me off for a Polaris ride to the surface.

 

[ChangeAgent]

of course there is a direct feed. these are emergency cylinders that also allow you to breath from them in a out of air situation (like a burst hose or frozen reg).

 

[happy-diver]

Keep a paint pen handy.

The ones I've come across have ingested water so much so that the corrosion in the threads made them U/S

So if this is not you, I would unscrew it every so often, and slather the threads in silicone, the rest of the time

Keep a paint pen handy.

 

[ChangeAgent]

I have not had any with internal corrosion. but what has happened to me is that the corrosion at the outside around the neck is strong and burrows under the o-ring and damages the o-ring seat.

 

[Edward3c]

of course there is a direct feed. these are emergency cylinders that also allow you to breath from them in a out of air situation (like a burst hose or frozen reg).

The other reason we stopped using them was the likelihood of legionnaires' disease from the bag.

It takes constant practice to be able to breath off the crack bottle, not something any agency now teaches.

 

[ChangeAgent]

I never thought about legionnaires' disease. and I do disinfect the bags regularly as it also extend the life of them. And yes you need to practise the breathing from the bag.

 

[happy-diver]

How much more internal do you want to be

make a project

Aluminum Passivation - AAA Air Support

Before the 1900s, commonly used metals were especially vulnerable to rust or corrosion. For example, this was the case with carbon steel, which will inevitably rust when exposed to moisture. This was a particularly problematic situation for applications and structures in wet climates and marine...

www.aaaairsupport.com

passivate aluminium at home - Google Suche

and slather it in silicone

Molycote 111

 

[ChangeAgent]

Thanks Happy-Diver. Nice information I did not know. Doing it at home seems to be a big project where special knowledge/tools is needed if I understand the process correctly. And there is the challenge of removing the old paint.
Does anybody know what Luxfer does when I buy a 80 cft tank from them? What is the outside treated with?

 

[happy-diver]

slather it in silicone without the and

You've got a square inch not even a cubed inch, of cleaning up of chipped paint and threads to do before you

slather it in silicone without the and

after you present some photos of your great cleaning work here for approval

before you slather it in silicone without the and

and grab a new oring