In article ,
David Lesher wrote:

My specific goal would be for a boneyard cart; able
to power either an impact wrench or saw.

I suspect that a small gasoline/propane motor and compressor will do you
better service for less money. Pick something annoying like a hopped up
chainsaw engine (2-stroke) to get the weight down if that's an issue.
And/or dual-purpose the motor to give the cart drive power.

The regulator needed is a big issue; even if breathing-type ones were
around; would they have enough CFM possible?

Hard to be sure, but I suppose you could hook a different regulator to
the appropriate tank connection. Can't change the tank connection too
much and still get a fill at the usual fill stations. If you got your
own high pressure compressor you could build to suit, but that is a
large chunk of change to play with.

How many CFM you need for a particular tool is basically going to set a
lower limit on how far you can draw down the tank and still have it flow
adequately. The FD response indicates hope for 10 minutes or so of use,
at least with their tools. For intermittent use you could also futz
around with feeding a 150PSI tank from the high pressure regulator, and
feeding your tool 90PSI (or whatever) from that, with more weight to
drag and increased complexity/expense.

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