Twinning Walter Kiddie 72s

[Evans]

A friend of mine got a pair of matching Walter Kidde steel 72s for cheap. They're in hydro and pretty much spotless inside, so an idea is to twin them up. The thing about these tanks, though is they seem really top-heavy, which an old guy at the LDS confirmed--that these old Walter Kidde tanks are unusually top-heavy (they also have an unusual shape to the top, but I think he said they are modern, straight-threaded). So what I am wondering is if anyone knows what kind of tanks I am talking about, has any experience with them as twins, and can comment about whether they are too strangely balanced to use well and in trim as manifold doubles.

Also if it would be impossible to get fitting bands for them. Any advise would be appreciated.

 

[wjbrandt]

Caution, you might check the original hydro date. WK has not manufactured tanks I believe since the late 80's. Luxfer bought them out, but not the liability. They may have some problems fragmenting. When attending a PSI cert class, they recommend staying away from WK tanks. Our shop will not fill them. Good Luck

 

[TwoBitTxn]

Are you sure they are steel?

TwoBit

 

[Evans]

Are you sure they are steel?

TwoBit

Yes. I'm sure. These aren't the bad alloy aluminum. They are steel 72s. In fact, hold on...

They are DOT 3AA 2250. Earliest hydro is '74 (with a plus). They are straight-thread valves (not the old tapered ones).

The only thing about them is that at the top they don't make a graceful curve where the cylinder starts sloping in toward the neck. Instead they have a sharp angle there. And they seem very top-heavy to the point my friend has trouble trimming out diving one as a single. If someone has any actual experience with these I'd like to hear if there are problems twinning them up.


Edit: I just realized I probably should have posted this in the Tanks, bands and manifolds forum. Sorry.

 

[SDAnderson]

Edit: I just realized I probably should have posted this in the Tanks, bands and manifolds forum. Sorry.

No problem, happy to help.

 

[jbd]

Yes. I'm sure. These aren't the bad alloy aluminum. They are steel 72s. In fact, hold on...

They are DOT 3AA 2250. Earliest hydro is '74 (with a plus). They are straight-thread valves (not the old tapered ones).

The only thing about them is that at the top they don't make a graceful curve where the cylinder starts sloping in toward the neck. Instead they have a sharp angle there. And they seem very top-heavy to the point my friend has trouble trimming out diving one as a single. If someone has any actual experience with these I'd like to hear if there are problems twinning them up.


Edit: I just realized I probably should have posted this in the Tanks, bands and manifolds forum. Sorry.

The description you give sounds just like some welding tanks I saw today at the local welding shop.

 

[Evans]

The description you give sounds just like some welding tanks I saw today at the local welding shop.

Oh? I didn't know welding tanks took straight-thread K-valves.

I think I've come to the wrong place.

 

[DA Aquamaster]

I have seen the type of steel 72's you describe. I had an option to buy a couple used several years ago but passed on them as they were just so darned homely looking.

Caution, you might check the original hydro date. WK has not manufactured tanks I believe since the late 80's. Luxfer bought them out, but not the liability. They may have some problems fragmenting. When attending a PSI cert class, they recommend staying away from WK tanks. Our shop will not fill them. Good Luck

Walter Kidde's aluminum tanks used 6351 alloy unitil they stopped making scuba tanks in 1991, about two and a half years after Luxfer stopped using that alloy.

In my expereince, Walter Kidde AL80's demonstrate less expansion during hydro test than Luxfer AL80's and are generally heavier in construction. They are prone to the same potential for sustained load cracking as the 6351 Luxfer tanks but I'd sooner own a 6351 alloy Walter Kidde AL 80 than a 6351 alloy Luxfer of the same period as the Walter Kidde AL 80's are stronger tanks. But I am also not concerned with filling 6351 tansk as long as they have a current hydro test and an annual eddy current inspection. In nay event, I'd take the advice from your PSI class with a large grain of salt as there is absolutely no evidence to support the claim that Walter Kidde tanks are more likley to "fragment".

 

[Evans]

I have seen the type of steel 72's you describe. I had an option to buy a couple used several years ago but passed on them as they were just so darned homely looking.

They are homely. In fact, they're painted yellow.

The horror.

But they were cheap. Kim (the owner) loves them because they're "retro."

 

[DA Aquamaster]

The ones I had a shot at buying were orange up to the sharp break at the shoulder and from the break upward they were yellow. Ugh.

Another turnoff was that the guy selling them had a regulator, fins, wet suit, etc he was offerring as well and he pulled everything but the tank out of an old 30 gallon civil defence water container. It all looked really crinkly form being in there for a couple decades and it made me wonder what the tanks would be like inside.