What's needed to double older LP72's

[jl in ca]

Hello all

I've searched a lot and can't seem to piece together info on what I'll need to double the LP72's I listed for sale a while back (and still have listed).

First, WHY?: Aside from them not selling, I need/want added gas. I have a couple recently acquired HP130's from folks on Scuba Board that are great when I can hop over to the LDS between beach dives but discovered that most my boat fills only net me about 2850psi based on what they can fill at and once they hit the cold CA water - bummer. I'm a big guy, enjoy long dives and use more gas in cold CA water. I do not need redundant first stages for tec and actually prefer not to buy/service two, etc.

Solution: I have 4 older LP72's that just passed visual and are in hydro I can turn into doubles. Again, I already own the tanks so working with what I have. They are + rated and the boats have no problem filling to 3000 psi on those which results in the same 2850psi cold pressure - nice! Those as doubles with that fill and add to that (I swear) two LP72s feel lighter than one HP130s and will have very good buoyancy/stability, etc - extra nice!

What I think I need to know: tank bands and manifolds. I see older single outlet manifolds (look to be as vintage as the tanks I have) on ebay and I'm good with doing my own service - reasonable route? But what spacing? I suppose that depends on what bands - so what bands (diameter and spacing again?) I can measure the diameter of the tanks of course but don't want to go about buying bands and THEN try to find manifolds only to realize I did something I should not have. I already own enough "extra" gear from my Craig's List finds, including these LP72's, lol.

Anyway, suggestions/links/info appreciated as always!

Joe

 

[runsongas]

if you go with the vintage manifold, you will need to match the bands to them as the spacing is different. piranha has 6.7 inch bands, dgx is out of stock.

else with a modern manifold with 8.5 inch spacing, you have more leeway on the bands due to adjustability and can use 7 inch bands or even 7.25 inch with a rubber spacer.

 

[Gone for diving]

I have 3 sets. Great doubles.
7mm wetsuit no lead.

If you have standard 3/4 thread neck
Get the cheap $100ish 200 bar manifold.
And go to a fab shop and get 20 gauge ss sheared 2-2.5inch wide x 4 ft long . If you can measure and drill a few holes you can make your own bands. Here is drawing for my bands and a few pictures

 

[jl in ca]

if you go with the vintage manifold, you will need to match the bands to them as the spacing is different. piranha has 6.7 inch bands, dgx is out of stock

else with a modern manifold with 8.5 inch spacing, you have more leeway on the bands due to adjustability and can use 7 inch bands or even 7.25 inch with a rubber spacer.

thanks - that helps.

 

[jl in ca]

I have 3 sets. Great doubles.
7mm wetsuit no lead.

[If you have standard 3/4 thread neck
Get the cheap $100ish 200 bar manifold.
And go to a fab shop and get 20 gauge ss sheared 2-2.5inch wide x 4 ft long . If you can and measure and drill a few holes you can make your own bands. Here is drawing for my bands and a few pictures

Nice! Did you have them welded at the overlap too? I work in the beverage industry and I’m sure the guys would weld them up for me. I “think” it’s the standard neck. Isn’t the really old small neck sure. I have one of those but it’s a wall hanger now.

 

[jl in ca]

Stupid question. With a modern manifold that has dual outlets, if you only have a regulator on one side and open that valve and the isolator, gas flows from both tanks correct?

 

[Bowers]

Stupid question. With a modern manifold that has dual outlets, if you only have a regulator on one side and open that valve and the isolator, gas flows from both tanks correct?

Yes, just plug the other valve if your concerned of accidentally turning it on and loosing air.

 

[happy-diver]

Used Vintage Scuba Double Tank Manifold | eBay

Used Dual Tank Bands | eBay

Make them nice man

and throw on a freedom plate with the money you save

 

[jl in ca]

So here again is my confusion - those bands above on eBay say they are for 8” diameter tanks... 72’s are smaller than that so those bands won’t work with vintage manifold correct? To use that vintage manifold needs the bands linked below as I understand it:

LP72 tank bands

then the spacing is right with the vintage manifold listed?

 

[happy-diver]

Yes perfect, it's me that is confusing

or these

Vintage At-Pa Stailess Steel Doubles Bands for 71.2 cu. ft. Steel cylinders | eBay


Be patient and grab what you need when you decide how you want to set them up