In Line/ Portable Air Tank Out of a Propane Tank

This is a old air tank that I use for starting fires and for filling my air cannon.

This tank was made with parts that where on hand a many many years ago. I had to take it apart because of a small leak and wanted to show how it was made.

Precautions
Use an EMPTY propane tank. You don't want gas leaking out and causing an explosion. Also compressed air can be dangerous. I'm not sure what a propane tank is rated for but keeping the PSI at a reasonable amount should be OK.

Step 1: Whats Needed

Parts (All in sizes inches)

standard EMPTY BBQ propane tank with vale removed. Preferably newer then the one I used
Air gauge 0-100 PSI (could go higher then 100)
1/4 female T
1/4 T male/female though female take off
1/4 male nipple
3/4 to 1/2 reducer
1/2 to 1/4 reducer
2 female air couplings
pipe joint compound

Tools

5/8 wrench
11/16 wrecnh
3/4 wrench
3/8 to 1-1/4 adjustable wrench (1" wrench)

If needed, a regular pipe wrench .

Step 2: Removing the Propane Tank Valve.

I am not so sure on this part. Find a wrench that fits and apply some torque.

Step 3: 3/4 to 1/2 Reducer

Apply joint compound around threads and screw it in. The reducer needs to be very tight so it does not come lose.

Step 4: 1/2 to 1/4 Reducer

Apply joint compound around threads and screw it in. A 3/4 wrench should tighten it.

Step 5: 1/4 Male/femal Through Female Take Off

Apply joint compound around bottom thread and screw it in. Tighten the T with a 3/4 wrench to where it points at where the gap is in the rim/handle on the tank.

Step 6: Gauge

Apply joint compound around threads and screw in the air gauge. Tighten with wrench to where the the text is readable and not lopsided. I used a 0-100 PSI but higher is OK. The compressor I use only puts out 115 PSI.

Step 7: 1/4 Male Nipple

Apply joint compound around one of the threads and screw it in. Tighten with wrench.

Step 8: 1/4 Female T

Apply joint compound around threads of the nipple and tighten the with a wrench to the T is in line with the other T.

Step 9: Air Couplings

This can be done 2 ways I prefer using one coupling.

2 couplings
Apply joint compound around threads of each one and screw and tighten them into both sides of the T
Use step 10 to fill the tank.

1 coupling
or just one on the side by the gauge and use step 11 to fill the tank.

Step 10: How to Fill It OP.1

Not so safe way. This was my original way of filling the tank.

2 1/4 male couplings
1/4 male ball valve.

Step 11: How to Fill It OP.2

The safer way. Also easier to fill the tank.

1/4 male coupling
1/4 male ball valve

This also makes the tank a bit more portable and with the ball valve handle inside the rim. Chances the valve will open are slim.

Step 12: Test for Leaks and Fill Up.

Test for leaks by connecting the male coupling to the air line and turn the ball valve to open.

Look for any bubbling of the joint compound at the connections.

If there are not leaks then it is good to use.

Keeping the tank inline should help keep the pressure longer before the compressor cycles. Close the valve and release the coupling and you have a portable tank for airing tires, starting fires, and filling air cannons.