Please just find a great sale on used actual SCUBA tanks. I know some of the pioneering divers rigged up some stuff like you suggest and most of them survived, but why take the chance today?
theskull
theskull
converting fireman tanks to scuba
- Thread starter mirrocraft
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Creed
Contributor
I've got 4 45cf steel Survivair tanks. Work great. All passed hydro and vis with flying colors. Two are set up as small singles, and 2 are set up as doubles. Picked the lot up for $20.
I even have 5 of the little Survivair 14cf tanks, with 2 pairs set up as doubles. They were originally marketed with a modified USD Aquarius as the regulator, so the manifold has a standard SCUBA style yolk outlet.
Short answer: if it's a steel tank with a standard sized neck and it passes hydro and vis, by definition it will be as safe as any other steel tank. The only caveat to this is that they may not be galvanized. In that case, you'd either want to repaint them with Galvalite, or only use them in fresh water, and be careful about watching for corrosion.
I even have 5 of the little Survivair 14cf tanks, with 2 pairs set up as doubles. They were originally marketed with a modified USD Aquarius as the regulator, so the manifold has a standard SCUBA style yolk outlet.
Short answer: if it's a steel tank with a standard sized neck and it passes hydro and vis, by definition it will be as safe as any other steel tank. The only caveat to this is that they may not be galvanized. In that case, you'd either want to repaint them with Galvalite, or only use them in fresh water, and be careful about watching for corrosion.
OP
mirrocraft
Contributor
just to put this out there im not planning on using htese taks as a primary support system i dive with high pressusre steel 100s i also have then set up as double i just like playing with stuff and building my own gear for fun i dont cave dive with it unless i really like the way it works
paulwall
Contributor
mirrocraft:
In answer to your question, newer tanks use a 3/4" valve opening, and older tanks used a 7/8" valve opening. Make sure the threads are the same pitch, or you may be shooting the valve out of the top of the tank at pressure.
I'd measure the old valves/threads and try to match that to the valves available. I've seen 7/8" valves available on Ebay and the classifieds, here.
pescador775
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The original steel fireman tanks were rated 2015 psi and used a 1/2 inch NPS O ring. The neck opening was about 3/4 inch across. I don't know what you have, 1 inch across and 2260 WP? Could be a dive tank thread, dunno. Anyway, the old White Stag manifolds and K valves used the 1/2 inch O ring thread. Last year, a load of them were auctioned off on EBay over a period of months. A double rig using this manifold could be used for recompression. Fill one tank with oxygen and the other with air or nitrox. Jump in (or fall in) with the air tank valve on and go to bottom. Come up slowly to 30 feet. Turn off air and turn on oxygen. The WS manifold is ideal for this. Well, somebody will have some kind of dumb comment like "is it O2 safe?" , or is anything safe?
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