Twin 50's

[treasureman]

I finally got the two 50 cu ft tanks i won on ebay in. I had asked the seller to hold on to them for me for a month while i was on my world tour.

Got them in. they are nice, clean white USD survivair with post valves three quarter inch with J. They have the old lead slug plug in front of the burst disk, so that has to go.

I have not decided what valves to use to twin them up, but I would like to do that. I trhew my RAm on one tank, and it looks so beautiful. Harkens me back to my newbie diver days.

So now i need to look for twin bands of the correct size. (what size does the fifties take anyone), and then decide if i want to use a Simon beans type of harness, or use a backpack type of harness. Do harnes holes need to be cut into the bands so they can be used with the SB style of harness???

lastly I need to figure out if I want to go with a solid twin manifold or the type which bolts each tank with the middle maifold/

So many choices...

I cranked the valve off both tanks. They are white inside looks like a painted finish, and I saw only the smallest little tiniest bit of rust in the bottom. last hydro was 97.

They are only marked DOT . here in canada I was told they would not hydro because it diod not say TC (transport canada). Of course being shrewd, I expolained that the olkder cylinders had ICC (interstate commerce commission stamped into them, and DOT ( department of Transport former name for the now TC Transport canada). That seemed to do it for them. This week I will send one off them the other,.

I forget who it was that had the triples that he had refinished. He stripped the tanks with naval gelly..got lots of that, then did a cold galvanizing, how many coats etc type of material used etc.

Any help, as the finiosh has seen better days. I have not decided yet to finish in the same white USD used or go to the nice navy grey colour.

[captain]

This is what you should paint them with. Get it in a quart can (about $30 US) and roll on 3 coats with a foam roller.

http://www.zincrich.com/p_galvilite.asp

[John Lundy]

http://www.zincrich.com/p_galvilite.asp[/quote]

Captain,
I have a set of USD alum triples that are yellow now. I would like to paint them with the above finish. Do you have to strip the paint first, or could you paint over the existing finish?

Thanks,
John

[captain]

For maximum protection they should be stripped to bare metal. The zinc in the coating needs to be in contact with the metal to provide galvanic protection.

[treasureman]

I used the captains suggestion. I streipped my tanks to bare metal by sand blasting to less than 1 micron. I apl;ied the "Galvilite" three coats with a foam roller. expensive stuff, but it goes a long way.

You have to stir it copmpletely to mix it. One quart weighs about 15 pounds. 95% zinc.

It is a really nice finish, looks great.

Glad Captain had the knowledge and passed it on. One quart can do five or six tanks I would imagine. I bought another 72 galvinized finish which I will clean up, then do with the Galvilite. Do use a ventilated area, and DO NOT get any water on it when it is wet., as this will cause a burst of hydrogen gas which is quite volatile.

You can accelerate the drying with a small heater, or it will dry by itself in half an hour to the touch.

Great stuff

[duckbill]

http://www.zincrich.com/p_galvilite.asp

Captain,
I have a set of USD alum triples that are yellow now. I would like to paint them with the above finish.[/quote]

Does zinc react with aluminum?

[captain]

I don't see the need to paint the aluminum with it. It is used mainly to prevent rust on steel. Aluminum doesn't need paint other than for cosmetic reasons.

[duckbill]

I don't see the need to paint the aluminum with it. It is used mainly to prevent rust on steel. Aluminum doesn't need paint other than for cosmetic reasons.

I'm just wondering which is more reactive, and how will they react together? Will the zinc "eat" or oxidize the aluminum, making for a poor bond, or worse? I would recommend just using silver paint on aluminum if that is the color desired, John.

[luis]

This is a quote from the Luxfer web site:
"Use only paints specifically recommended for use on aluminum surfaces. "

http://www.luxfercylinders.com./support ... /cm5.shtml

If I recall correctly zinc is lower in the galvanic scale (meaning aluminum is more noble), but they are not far apart. It is probably best not to have dissimilar metals in contact with aluminum if it can be avoided. I don't know how this applies to a paint rich in zinc.

[duckbill]

Well, after a web search I have come to know that an aluminum-zinc alloy exists. So, are there materials which are fine together once alloyed, but a surface-to-surface contact between the two metals would not be recommended?
Just go with silver paint, if you must, and be safe. That's what I'd do. Probably a whole lot cheaper and more durable, too.

[duckbill]

Just go with silver paint, if you must, and be safe. That's what I'd do. Probably a whole lot cheaper and more durable, too.

Actually, I LIKE U.S.Divers yellow. If they're vintage, why not stick with the original finish? That is really what I would do!