SpudFiles

So I got a tank from my uncle (free) and made myself a portable air tank for my cannons. It holds 8 gallons and I fill it to 350psi which gives me a lot of air when shooting cannons at 80psi or so (well not a lot of shots with Plague…). It may take a long time to fill but it’s worth it because I can go for a long time without refilling. I have a regulator that I use with it that takes it down to 0—180psi so it works with any cannon
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The entire setup while filling

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And the fill and gauge on the top

It looks like a modified Propane tank. If it is be aware they are not painted or sealed against moisture on the inside. Check for rust on the inside after use and remember the working pressure is only rated for about 260 PSI. Minimum burst pressure is 4X the working pressure.

Nice tank mod. Stay safe.

yeah it is a propane tank and tomarrow when i got the store i am picking up the paint to seal the inside against rust. but i figured it would be ok for 2 days. and im not going to go any higher than th 350 for the saftey reason and when complety full it holds over 3 times the volume that my shop compressor holds...

Cool. I did the same thing with an old air bottle, however I only fill it to 100 psi though because its really old.

I've been thinking of making or buying a tank. I have a comp with a big tank at my dads house but just a tankless comp at my moms house...

Great job with yours!!!

I think it was DR that used a/some stick(s) of 4" PVC capped at the ends as expansion chambers for his compressor in his garage. Each 10' section will give you 6.5 gallons of extra space. It's cheap, easy to make, can be stored up and out of the way... just don't let it get too cold where you store it and you're all good.

How did you remove the valve from the propane tank?

I once used a pair of vice grips and a long pipe. I have seen a specially made socket to go in an impact to remove the valve. It was made by welding together 4 peices of flat bar to form a box around the valve.

boyntonstu wrote:How did you remove the valve from the propane tank?

smartass answer: i unscrewed it

normal answer: 2 people, a big wrench, and a cheeter pipe

nice... now you can fill it first and then feed air intake with pressurised air

How much do they charge you to fill it with propane where you live? If you find anyone willing to fill a bottle that is modified you can get allot of gas.

@poland, i do not follow what your taking about

@spudfarm, no one will ever fill a modified bottle, all regulations and laws prevent it, also the fill stations do not have quick connects on them so that is anougher reason they couldnt fill it. anouther thing is why would i want to fill it with propane?

c11man wrote:

boyntonstu wrote:How did you remove the valve from the propane tank?

smartass answer: i unscrewed it

normal answer: 2 people, a big wrench, and a cheeter pipe

Note that the valve is often set with some kind of pipe joint compound that sets up tight. I found it much easier to remove the valve if I warm it up until the paint near the valve discolors. After that, much less force is needed to unscrew the valve.
DANGER The tank will be full of propane vapor. If it is a really old tank and the valve was left open, it may have a propane air mix. Do not do this with a propane tank that may have air in it. Only do this with a tank that still has some static pressure in it. (vents propane when the valve is opened). Open the valve and light it. You do not want high pressure to build while heating. Heat the valve with a propane torch until it is smoking hot. Let it cool some and apply the wrench. No cheater bar is needed anymore.
I prepared several tanks for future modifications this way. Note the one on the right, normal plumbing reducers are screwed in to fit 1/4 inch air tank stuff. I used that tank for a portable air tank once.

The smartass answer is the right one. I unscrew them. 2 people is not needed. Neither is a cheater bar unless you are the 98 lb weakling.


Note the paint on the neck of the tank is slightly darker. This is from being hot. Just enough heat was used to break down the sealant.

you can first fill the tank to 50 psi or so and then use that as a source of pressurised air for the air intake... boyntonstu has posted a video of this procedure... it shortens filling time and probably increases max pressure too

@tech what i read on the internet said to do exactly as you said. i would have done this except for one small issue, i do not own a propane torch. so i decided a wrench and cheeter pipe would have to do. also the second person was just to hold the tank as it was much easier to call my bro out than set up a clamp to hold it in place.

and poland if you will look at the first pic you will see the yellow hose feeding air to the inlet of the ac compressor. i have been doing this for a while before Stu ever posted it (but oh well) . but yes i can use a regulaor i have to bring it down to the 40~50psi that i run into the AC compressor. not useing a pressureized inlet would make it take far too long and with too many breaks to cool down to be remotely practicle. 8 gallons at 350psi is alot of air....