Outer Limits 4x4 Board

9kg gas bottle = 21lt.
I assume TP = test pressure = to 3.3 MPA = 493psi

What is the working pressure of a LPG bottle?

My conclusion is that a $30/40 bunnings LPG bottle plus some fittings = cheap air reservoir. Could even get two at that price!

Is there a reason why I can't find any info on other people doing such a thing?

OR second idea is a argon bottle. My supagas bottle is rated to 4400psi

The argon bottle is actually a nicer shape to put under the car.

Any other ideas?

As long as don't have pay rental on the bottle every year I have thought about using a disposeable(sp) argon canister used in the tiny migs.

juls wrote:9kg gas bottle = 21lt.
I assume TP = test pressure = to 3.3 MPA = 493psi

What is the working pressure of a LPG bottle?

My conclusion is that a $30/40 bunnings LPG bottle plus some fittings = cheap air reservoir. Could even get two at that price!

Is there a reason why I can't find any info on other people doing such a thing?

OR second idea is a argon bottle. My supagas bottle is rated to 4400psi

The argon bottle is actually a nicer shape to put under the car.

Any other ideas?

The gas bottle would do fine as far as pressure goes, it should also have a design pressure stamped on it to tell you what pressure it is designed to carry on a daily basis.

The biggest issue is getting a drain plug fitted, but if you tmount the bottle upside down and do a little manifold/valve work then this shouldn't be too hard.

A 9kg bottle holds about 23Lt of air.

Cheers

Bunnings sell "Recharge cylinders" made for 120psi of compressed air for $49. They hold 16 litres and come with a gauge, mounting brackets, a drain and can be filled via the schrader valve(tyre valve) fitted, at any servo(or compressor).
Much cleaner than an old gas bottle without a drain.
http://www.gmcompany.com.au/index.cfm?m ... ts&pid=672

MINE.. I didn't like blue!

Now, just a query, how many tyre's can be inflated/topped up from a tank like this without refilling?
(thinking of a similar setup in my j-top- limited space)

Edit: By the way Juls, check out HIANUFGQ's post HERE it's a ripper with an alternative bottle

I don't know yet as I haven't had a chance to use it but I would imagine it would reinflate a couple of 31's from 15 to 30psi no worries.

I'd like to know if you can operate any air tools from a tank that size too......
got a mate with one, about 25l shaped like a donut, might go over tomorrow and test his out for these things. As I'm sure with a tank, one could easily get away with using a cheaper compressor with load taken off it..

I'll do some tests and report back!

Mr Sausage wrote:Now, just a query, how many tyre's can be inflated/topped up from a tank like this without refilling?

You might be lucky to get 2 half filled, but that depends on if you can liquidise the air in it or not.

The big problem is the source of filling the tank with air. The servos and home compressors will only achieve a microscopic amount of pressure compared to what BOC or AirLiquid could fill it.

My 12CFM workshop compressor has a medium sized tank, heaps bigger than the GMC one above and it will not fill a queen size air mattress enough to sleep on at zero pressure.

get liquid CO2 put into it - short of it freezing over, or blowing the burst disk in the sun, it'd fill tyres forever =)

Ive used this for about 12 months and has worked great.
Dose 4x 29x7x15 tires from 14 to 25 in 50 SECONDS, enough to do 10 to 12 tires. refills $15. After the first 4 you need to let it warm up a bit or it will freeze. Keep the bottle upright and if the gauge on the reg starts going up it means its starting to freeze, just back off the pressure on the reg and bleed it off until it warms up a bit, a couple of minuets is enough on a warm day. did notice after topping up tires that it drops a couple pounds after a day and stays there.
Not sure if Co2 is a problem in tires. So far so good.
http://www.ozito.com.au/productinfo.asp ... d=OZCO2FCA

people have been using co2 for years in tyre on enduro bikes, cicuit racers use nitrogen.

Try and pick up a worn out medium size compressor from a tip shop and take off all the compression motor and electric motor that way you have a drain and proberly a pressure switch , i know my arb engine bay mounted compressor has a pressure switch so if the one your using has one you could wire it into the tank insteed of the compresor.(ps the reason my compressor has a pressure switch is cos it has a built in tank but its only half the size of a beer can i think its something to do with running air lockers).

has anyone seen those gmc air tanks anywhere in sydney? ive tried multiple places and no1 has it or anything like it.

Mr Sausage wrote:I'd like to know if you can operate any air tools from a tank that size too......!

I run an impact wrench off a 9lt tank
Will undo 2 nuts with that amount of air

the troube with comverting an LPG bottle is LEFT HAND THREAD. makes it harder to adapt fittings to, it can be done, but its harder and will cost more.

had a bunnings GMC type special and wasnt happy with it because I had to have it mounted upside down which meant no drain and the line in/out was on the bottom so any moisture and oil came out the hose when inflating.

went and brought one of these:
http://cgi.ebay.com.au/BOSS-Air-Tank-9- ... dZViewItem

best quality I have seen around, prices cant be beaten, alloy so its LIGHT (when it turned up I thought they had sent me an empty box) it weighs 2.2kg and the quality is top notch, the welds look to be done by machine and not by hand, and plenty of ports for lines in/out, drain, switch and pressure safety valve.

well and truly worth it.

mrw82 wrote:the troube with comverting an LPG bottle is LEFT HAND THREAD. makes it harder to adapt fittings to, it can be done, but its harder and will cost more.

A POL to BSP fitting is what you want. I bought one for another application for about $20.

got mine from a truck wreckers for air brakes ran 2 air lockers and pumped up tyres great was using a blue tounge compressor tank also had heaps of fittings made into it hope this helps

mrw82 wrote: went and brought one of these:
http://cgi.ebay.com.au/BOSS-Air-Tank-9- ... dZViewItem

best quality I have seen around, prices cant be beaten, alloy so its LIGHT (when it turned up I thought they had sent me an empty box) it weighs 2.2kg and the quality is top notch, the welds look to be done by machine and not by hand, and plenty of ports for lines in/out, drain, switch and pressure safety valve.

well and truly worth it.

i got one of these as well.. bloody neat welds and it is truly light as a feather. tons of ports. one on one end so can be used as a drain. still waiting on hoses before i can test the sucker out :(

i've been using a lpg bottle for a few years with no probs. as for the left handed thread, all i did was remove the said bung from the bottle, cut off excess tap etc and silver solder a 5/16 barb on.

Its not in Sydney, but I found the GMC tanks in Bunnings in Bayswater Vic last night in the tool section next to the air compressors. My local Bunnings doesnt seem to have them.

So give Bunnings tool section a shot, either try multiple bunnings or ask if they can order them in.

joshy wrote:has anyone seen those gmc air tanks anywhere in sydney? ive tried multiple places and no1 has it or anything like it.

Ive seen them in Bunnings in Sydney, Im regularly in Taren Point, Rockdale or Botany bunnings, I saw the GMC gear in one of these three, cant remember which.

cheers guys. ive tried a few bunnings, if i get a chance ill check out the ones you mentioned or just try and order it in.

Like Adam GQ said, try the truck wreckers.

I just picked up a 15lt tank for $10, with a drain plug and two other outlets, all it need is a paint.

yep and i bet they last longer than a GMC one