Scuba tank to power air tools?

[Flot]

Aha, I see the misunderstanding.

Pescador, what I meant was - I fully intend to use a scuba 1st stage as the INITIAL pressure regulator. I was under the impression that any 1st stage will output somewhere between 80-150 psi on the LP side, which seems like it would also be within range for a standard air tank. I figured then there must be some inexpensive hardware pressure regulators that would let me adjust the ~1xx psi down to whatever a particular tool worked best at. (I believe the nailer I borrowed preferred 80-90 psi)

As for the 1st stage failing, I'd rather have it fail on an air tool than fail on my back during a dive!

But I understand your concern and suggestions. I am sure my LDS has some old first stages lying around that were never picked up from repairs, etc, so I just want to find out how specific I should be in trying to locate one. I'll see what I can find.

Was thinking of a generic 1st stage, with something like THIS attached...

 

[pescador775]

I considered both alternatives. I suspected you were going to put a LP regulator in series but dismissed it (naahh, he can't be serious). Please don't do that unless you need a precision air pressure controller for spray painting. These cost about 20 bucks. Set the Scuba regulator to 100 +- 10 psi and leave it like that, connected to an LP hose of sufficient pliability and diameter. 1/4 inch oxygen hose or inert gas hose. Air tools use about 4 cfm. If you are planning on doing some sand blasting you will need a compressor. A tank would ice up and be depleted quickly. Then, you can also buy a Sears regulator or whatever if the compressor is not so equipped. A relief valve is normally part of the package also.

 

[dhampton82]

You can get a little compressor for about $100 at any hardware store. That would be less then getting 20 fills on your tanks and alot easier than running back and forth to the dive shop for fills.

 

[Flot]

You can get a little compressor for about $100 at any hardware store. That would be less then getting 20 fills on your tanks and alot easier than running back and forth to the dive shop for fills.

My garage has enough crap in it already. Besides last time I checked you could also buy dive lights, underwater housings, etc. hahaha.

Besides, the little bit of air I'll use for air tools is practically free - I always have 3 tanks somewhere between 1000-3000psi lying around. (I use less air than my buddies) Seems like a good solution for occasional use. My LDS by the way mentioned that they have a guy who stops by twice a week to fill his tanks, apparently he's a fence contractor. Sounds like it's working for him!

I did some ebay shopping and it seemed like the cheapest I could get a working 1st stage would be about $35-40 after shipping etc. Decided I may as well take this opportunity to buy a new 1st stage and reg for myself, since I've been diving with a cheapo that I bought from a friend 2 years ago. Seemed like a good way to 'recycle' my old 1st stage, and I'll still have the regulator to use as a spare.

 

[matt_54351]

just remember that cfm is also dependant on pressure. a lot of air tools are rated around 90psi, where as your tanks are rated at standard atmosphere pressure... so you will probalby get less working time than what the quick division answer (80/20=4min) would lead you to believe. the other thing you can do is once you get the pressure down a little put the tank out in the sun... hotter gas expands (or in a fixed volume like a scuba tank) the pressure increases. when you use the hotter the air at the same pressure, you are acutally using less air molecules to power the tool for every cf of air. it is a linear ratio, so if you doubble the temp of the tank (in C) at 1500pis tank pressure will go up to 3000 and you get more time from your tool. the tool will need more pressure at higher air temps, but you still make enough gain so can trick your tank that is down to 500 psi cold into finishing the job.

 

[pipedope]

Lots of people are making this more involved than it needs to be.

Most any scuba shop will have a quick connect adapter that will connect to your BC hose. Buy one.

Take the adapter with you to Lowes or Home Depot or a real hardware store and buy a standard air hose quick connect fitting to screw onto or into the adapter. Get the fittings for the air hose (male end and female end) and a length of air hose.

If you are picky you can have the IP of your regulator checked to make sure it is around 120 psi. Pretty much anything from about 80 to 140 psi is fine although the big framing nailers get a bit harsh at high pressure. Not a real problem but a good kick when you squeeze the trigger.

You can get a cheap 1st stage reg if you like but for the amount of use you are talking it is not needed.

BTW I carry my adapter and also an air chuck in my kit all the time. I have more than once used it to air up a tire that was low.

 

[pescador775]

Matt, both Scuba tank capacity and air tool flow rate are referenced to atmospheric pressure. Four cfm flow means 4 cfm free air (SCFM).

 

[matt_54351]

i have seen several tools rated at 90psi...

your regular tools may be rated at standard, but some of the big air eaters like sanders MAY be rated differently, like this one:

http://www.porter-cable.com/index.asp?e=547&p=5809

 

[rjk75]

Flot,

Just wondering how or what you eventually did to use your scuba tank?

I'm now in the same process of trying to adapt my old steel tank to
power my 18-ga Brad nailer. Any info you could provide would be very
helpful.

Thanks,

RJK75

 

[neil]

Here's a guy's website with pictures and explanation of how to use scuba to run tools.
http://www.saltypig.com/scuba/