Tanks from Cressi,Sherwood,Genesis.....

[Jean eve]

1.does anyone know about tanks from 'Cressi sub' , 'Sherwood','Genesis'...Do they produce their own tanks or they are come from company such as Luxfer,Pressed steel and Faber.Besides these three manufactures is there anymore tanks manufacturer?(espeacially manufacturer for steel tank).
2.When I send my tank for annual checking,they found that the interior of the tank(steel) has many small holes eaten by the rust.The explantion from them is I'd let go the air too fast and it create humidity inside the tank.But I hasn't do that before!How to prevent this and why there is some holes eaten by the rust?Any ideas??
3.To check the tank,I saw them just using a small light and put inside to see if there is any crack.Is this the way to check a tank?? :06:

*does anyone know which country ban for using Aluminum tanks besides Tahiti,French Polynesia.(I'm from Tahiti)

Thanks a lot!

 

[Groundhog246]

The pitting would certainly be from moisture, but more likely bad fills rather than letting air out too fast (unless you're in the habit of dumping all the air rapidly out of your tanks regularly.
On the fill front, possible causes are: Small amounts of water in the valve outlet from rinsing tank or otherwise wetting the valve without a regulator attached. Easily prevented by venting a small amount of air before hooking up the fill whip. Similarly water in end of the fill whip, most often encountered when filling tanks in a water bath and the end of the whip get's dunked. I'm told that PST recommends against using baths at fill stations due to this risk. Lastly, wet air from the compressor system itself, likely due to inadequate maintenance of the filter stacks or damage to them, possbily from not draining the compressor. The first two are more likely than the last.

I'm not aware of any country with a ban on aluminum cylinders. The only mfg of steel I'm aware of are Pressed Steel and Faber. Not sure about steel, but any aluminum Sherwood cylinders I've seen are Catalina's.

 

[Jean eve]

I would like to know more......Thanks

 

[Drew Sailbum]

3.To check the tank,I saw them just using a small light and put inside to see if there is any crack.Is this the way to check a tank?? :06:

That's basically how it's done. Some sort of a light is inserted into the cylinder and small mirrors are used to better examine the threads in the neck as well as the area under the crown of the tank. Sometimes a metal probe is used to help determine the depth of any small holes (pitting) which has occurred.

Some aluminum cylinders are checked with an eddy current device. This can help detect cracks in the area of the neck threads. These machines are not designed for use in steel tanks.

 

[aquaoren]

1.does anyone know about tanks from 'Cressi sub' , 'Sherwood','Genesis'...Do they produce their own tanks or they are come from company such as Luxfer,Pressed steel and Faber.Besides these three manufactures is there anymore tanks manufacturer?(espeacially manufacturer for steel tank).
2.When I send my tank for annual checking,they found that the interior of the tank(steel) has many small holes eaten by the rust.The explantion from them is I'd let go the air too fast and it create humidity inside the tank.But I hasn't do that before!How to prevent this and why there is some holes eaten by the rust?Any ideas??
3.To check the tank,I saw them just using a small light and put inside to see if there is any crack.Is this the way to check a tank?? :06:

*does anyone know which country ban for using Aluminum tanks besides Tahiti,French Polynesia.(I'm from Tahiti)

Thanks a lot!

Since steel tanks are more common in Europe, I am sure there are more companies over there who make steel tanks.
I know about couple of German companies, who make steel tanks: Mannesmann & Apoldaer Stahlflaschen. Heiser is an Austrian Company and Roth is a French one.
I would think that in many countries in Europe, you'll find at least one company that would make steel tanks.
Of course not all steel tanks are the same. There are big differences in the quality of the steel. From the companies I named, the Germans make the highest quality steel and use the most expensive production procedure.

 

[Poh]

Anyone know more about this company?Can't find their web site!Thanks.