I want to use a scuba air tank (3000psi) to run air tools. I have a scuba compressor and live on a boat.

by Brian
(Coastal Australia)

I want to use a scuba air tank (3000psi) to run air tools. I have a scuba compressor and live on a boat.

What regulator to use?
What valve?
Connections?

SCUBA tank for breathable, diving air
SCUBA tank for breathable, diving air

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Your air tools don’t much care where the air they run on comes from, as long as the flow is adequate and the pressure is within their operating range.

Can you run air tools with air from a scuba tank? I don’t see why not, though that would have to get expensive over time.

Brian, I have no experience with scuba or high pressure air so I cannot recommend a regulator or parts.

The regulator(s) you use will have to allow sufficient flow for the air tools of choice, which is, I expect, much greater than that demanded of a breathing regulator.

You need to talk to the regulator companies directly, to find out what range of regulators you will need.

As to plumbing, once you get down to 100 PSI or so, any brass fittings, industrial air quality poly tube or rubber air line hose, etc. will work fine.

It’s the getting from a low flow 3000# air supply into a low pressure high volume flow that I can’t comment on.

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SCUBA compressed air source
by: Steve Hericks

I use exactly this setup and sell them to friends.

What I do is buy an older scuba regulator that a diver might be reluctant to trust his life to and modify it.

A SCUBA first stage regulator outputs 140PSI. I first strip all the hoses off of it and leave 1 HP and 2 LP ports open. The HP port is 7/16-20 thread and usually so is a submersible pressure gauge (SPG). If the SPG is in good condition, I remove the SPG from the hose and threaded directly into the valve. Sometimes it has a permanently attached small stem with o-ring to seal to the HP hose. Cut the stem off with a hack saw add add an o-ring to the gauge stem.

Sometimes I throw the gauge away and put a new liquid filled non-SPG gauge on it. 5000psi Liquid filled 2-1/2″ gauge with a 7/16-20TPI(M) stem are not uncommon. They have the benefit of having an adjustable lock nut so when you thread the gauge fully and align the gauge, then lock it in the position where you want to read it.

In one LP port (3/8-24TPI)I put a pressure relief valve in case the regulator freezes, I don’t want HP going to my tool. Its set at about 200-220 pop-off. (its standard gear on dry suit rigs.

In the second LP port, I add a 1/4MPT x 3/8-24TPI(M) adapter onto which I add a standard air quick coupler (1/4FPT).

That’s it.

Provides 140PSI air perfectly.

When I want lower pressure, I have a standard low pressure regulator with a male quick coupler on the input and a female on the outlet I can just stack onto the first stage regulator.

I typically sell these for $80 for those which are older and with a SPG and $100 for those which are newer and have a new gauge.

I could sell the gauge, relief valve and MPT adapter for about $50 if you want to provide your own regulator. I use these setups for an air source for pneumatic cannon (t-shirt launchers).