Does anyone have experience using rock sliders to store compressed air? What would be the maximum recommended psi for 0.120" walled box tube?
The interior volume of the sliders I'm thinking of is around 2.5 gallons.

I've seen it done. I can't remember his name, but someone w/ SCCX has done it on his. He uses them as small tanks supplied by an onboard compressor.

Jim

Yep, I remember this being discussed a while back - using the step rails as either tanks or as a conduit for the air... Wasn't all that long ago, either. Try various search terms and see if you get a hit?

Warmonger is one of them. A couple other people on AF have done it too.

Warmonger didn't use the step rails as tanks. He mounted his tanks in the forward fender wells. For more info, see his Installation page.

Ahhh.. but he did.. it is a recent add on..

What! And he didn't tell me. How dare him.

What would you do to keep condensation from forming inside the sliders and rusting them from the inside out?

Fill the sliders from an air source that has a filter to trap water, also the EOE sliders(not sure of Calmini or others) are made from 3/16" tubing so it's going to take quite a bit of time for them to ever rust through...I think we will all be eating worms by then

Here's a writeup that somebody did for their slider/tank.

http://personal.atl.bellsouth.net/rdu/e/_/e_dan/section_air_compressor.html

I just made a tank out of an old stainless steel fire extinguisher. The walls are really thin, maybe only 1/16", but the gauge goes up to 200psi and the fire guy told me they are rated up to 500psi.

Steve

Just cause I don't know, but what kind of extinguisher was it (Dry Chemical (or an ABC rated extinguisher), Carbon Dioxide (or BC rated), or water (class A).

If you have a red extinguisher, it's most likely a Dry Chem or CO2 cylinder, so unless you have a water trap or have the extinguisher mounted near a heat source, you will need to make sure that no moisture gets into the cylinder, since the ABC and CO2 cylinders, while stainless, really like to rust up.

Of course, if you taked to the "fire guy" about it, I'm sure you'll be fine, but just in case others were now thinking about this as well, using one of those cylinders (especially an older one, which is what most people will come across) could possibly pose a hazard down the road.

If you want to be serious about preventing rust when using your sliders as air tanks, you could always pour a rust inhibitor (like POR-15) into the sliders, move them around to coat the inside, pour it out and then into the other slider to coat it.

I doubt that would work, wq. the preparation for POR 15 is pretty prohibitive, and the cost of enough POR 15 to coat the inside is prohibitive. It's great for paint on applications, but not for shake and bake. If you don't get it on EVERYWHERE it will rust in the areas that are not protected, and slowly make it's way aroung the POR. If you are gonna do something I would suggest a small silica gel pack (like they have in camera packaging) taped to the inside of the slider before welding. that'll do a good job of absorbing any extra water vapor.

It's really not worth the trouble, as FSR said, it'll take eons before the inside of a slider rusts out. it'd have to have ounces of water, not droplets.

Matt

Hey Jeff,

The extinguisher I got is a water type so hopefully that won't rust.

Heres a couple pics of it.




Roger Brown has a write up here on how he converted his ext. to a tank. He plans on emptying it once or twice a year.

Steve

PS. The best part is the tanks were free from a fire extinguisher refilling company.

Why were they free? They fail hydro?

The company I work for is right next door to the fire ext company and I just walked in and asked if they could donate any tanks for an air compressor project. I don't know the history behind them.

Steve

As a SCUBA diver, I have great respect for compressed air. Yes, SCUBA tanks have pressures measured in the thousands of pounds, but 125 psi being released violently will also ruin your day.

I hear ya Xterrain, as a mechanical engineer, I too know what pressure can do and how pressure vessals are made. I plan on being very careful with the tank.

Steve

Not to sound like a jerk Steve, but mechanical engineers can be some of the worst when it comes to personal safety around stuff like this. The knowledge base seems to instill a bit of overconfidence. A non mechanical engineer like myself would go back over there and ask if that extinguisher had failed hydrostatic testing. It just doesn't seem logical that a company would give away one that was still usable. Either way, good luck with your system.

Matt, I think Bryan is talking about this U.S. STANDARD FUEL TANK SEALER http://www.por15.com/cgi-bin/formrunner5...&ItemNumb=catp6 that is made by POR.

No offense taken, you're just trying to look out for my welfare and those around me.

Steve

Hey Benny, one of the reasons he hasn't mentioned it yet....He hasnt got the sliders installed and tested yet, he is still in the process of repainting them.....

Then I guess they're not really stainless then... Stainless doesn't rust.

I dig the sliders that the guy with the Toyota has - the round, tubular type. They match the roof rack, and being round (if they're thick enough) should be quite strong. That dude installed one helluva air system, wow.

Whoops, I have no clue what I was thinking there...

The water extinguishers are stainless. The CO2 and ABC are just painted. (while painted, those cylinders really like to rust up if mositure is left in them

I would hope not If they failed the physical test, then he'll know about it when his tank doesn't hold any pressure.

Someone probably left the cylinders, or a company they service is chaning over to ABC dry chem. They look old, and most individuals want a new extinguisher. The cylinder may be in perfect condition, but since water extinguishers are very limited in their use they just aren't as marketable as the Dry Chems. The only real benefit a water extinguisher has, is that it is cheaper and easier to refill (just tap water under pressure) than a dry chem, and it cleans up easier after use.

Hehehe. That's alright - I knew what ya meant...

They really do rust up pretty fast, those other types. Even the *chrome* extinguishers (which you may have been thinking about) are bad like that.

I pulled aside a Helium tank years ago for some future project, but the more I think about it, the less useful the tank seems. It's about 4' in height, but it weighs a freakin' ton!