"New" Twin 72s

[jamiep3]

After a couple of years of trying to find a nice matched pair of steel 72s to double up, I'm thinking of going with a couple of AL72s from Worthington. I've got a question though, I'm planning on using a late 60's / Early 70s backpack, with galvanized bands. Will putting the galvanized band on the brushed aluminum cylinder cause a corrosion problem?

I've considered putting plastic between the band and the cylinder, but am not sure what to use. The bands are 1 1/2" wide.

Suggestions welcomed.

[mistral]

I would suggest some strips of inner tube rubber. Its easy to work with, and will make for a good buffer between the bands and the aluminum cylinders

[Ron]

Hey I just saw your post Jamie, but you really shouldn't have any trouble locating two 72's that are of appropriate dimensions to double up. I have had several sets of double 72's now, and none of them match by manufacturer all the way. Just find two that are the same length (sometimes they are taller or shorter for some reason) and band them together.

You can do what you want as always, and I will give you no flack, but the buoyancy characteristics on the aluminum 72 are less than desirable for most diving. Plus, you can usually find 72's for like 50 bucks a piece locally. Have you checked craigslist or any local dive shops? Sometimes they have them around. My local dive shop has several just sitting in the back.

[captain]

Even 72's from the same manufacturer have variations in length and neck contour. At one time I had 10 of them and no two were exactly alike.

[jamiep3]

A few have come through my LDS, but they get snapped up fast. They are still popular for making modern doubles as well. I've got a couple of steels, but are too mismatched.

I figure with the manifold, they will be about a pound or two buoyant when empty, if need be, I can always put a little weight between the bands.

[Ron]

If you are going to spend the cash on new tanks, then I would suggest just getting aluminum 80's. They have almost identical buoyancy characteristics to aluminum 72's and you get 10-11 more cubic feet of gas in a twinset for what usually amounts to a decent cost savings as 80's are much more plentiful than 72's. Just a thought

[swimjim]

Double AL80's were my first double set. I found them terribly floaty when empty. Just my two centavo's. I have two 72 double sets with double iso manifolds and one set up vintage. I really like both much better then the 80's set up. YMMV

[Ron]

You had double aluminun 72's and found them less floaty? Maybe you had a different brand. The ones I used were luxfer and they were bad.

[swimjim]

Nope, steel 72's.

[Robohips77]

Check your pm