I've had a small fire extinguisher sitting around for a while and since I have more I decided to turn it into an air cannon. The acronym stands for "Nerf Air Soft Homemade" since it can shoot Nerf darts, airsoft BBs, paper rockets (with plastic bottle fins!), and whatever else fits in that wonderful 1/2" barrel.

Those of you who are older and have more sense in you can shoot AA batteries, but be aware: these can be lethal if they hit a person in certain places. NEVER EVER shoot at a person, animal, or something you don't want to damage!

That said, let's get started. Here's the shopping list (or parts list if you're like me and have a 30' trailer of pure plumbing parts ;-)

(1) Pressure Gauge: Make sure it measures from 0-100 PSI (or near there), has an air fill valve, and 3/4" threads on the bottom.
(1) 1/2" x 3/4" Brass / Iron Adapter (threaded of course)
(3) 1/2" Brass / Iron Nipples (about 2" - 4" long, doesn't matter)
(1) 1/2" Brass / Iron Tee
(1) 1/2" PVC Male Adapter
(1) 1/2" Ball Valve (metal, threaded ends)
(1) Small Fire Extinguisher

That's it! On to the build...

Step 1: Disassemble the Extinguisher

Go outside, pull that pin, and enjoy emptying the extinguisher. Or have a weenie roast and then put out the fire with it. Either way, make sure it is completely empty.

Now depending on your extinguisher, you'll have to figure out how to unscrew the top from the tank. Mine had a metal label with a tab that I secured in a vise and then I used a wrench to loosen it. Turns out the one I have wasn't that tight. Not sure if they are all that way, but take courage! It will come off!

You can use a crescent wrench or channel locks on this guy.

Step 2: Assembly

For those of you who don't have a relative who is a plumber, I'll go over the basics of assembling iron pipe.

Take the sealing tape and wrap it around the threads as shown. Read the comment on the image too :-)

After 3-4 wraps you can just hold the tape on the pipe and snap the rest off (the tape on the roll). Now take some of that pipe-thread compound (we plumbers call it something else but it could give people the wrong impression... ok, ok, we call it dope :-) and lightly coat the taped area with it.

Now take a couple of wrenches (channel locks or crescent, heck even a small pipe wrench ;-) and tighten it up! Make sure it is in there pretty good. The nice thing with iron pipe and brass is that if it started leaking at a joint, you can just tighten it.

Now assemble the rest of the gun using the pictures.

I'd assemble it in these groups:

1. Extinguisher, nipple, tee.
2. Air Gauge, reducer, nipple.
3. Nipple, ball valve.

And then screw assemblies 2 and 3 into the other ends of the Tee as shown. Lastly, attach your barrel/attachment of choice.

Step 3: Testing and Firing

Now that it's built, it's time to test it! Take it outside (preferably) and pump it up to 30 PSI. Listen for any leaks and tighten any joints that are leaking (make sure there aren't any cracks).

If there aren't any leaks you're all clear. Load a dart in the barrel by removing the barrel and putting it in the back end (breach loader or box magazine coming later), put the barrel back on and fire!

I'll repeat myself for all ye builders, do not pressurize over 100 PSI!!!

Here's a video of a AA battery being shot at 100PSI. Video quality isn't that great, sorry about that...

Have fun, be safe, comment, and check back for updates:

- Breach loading barrel
- Box magazine barrel
- Gun-Mounted Pump
- And more!

--GoDoggie

Step 4: Add-Ons and Extras

Since I made this 'ible, I have modified my NASH gun. Here's some pics and what not so enjoy! Maybe it'll give you some ideas on how to take it to the next level!

The "scope" was from a cheapo airsoft gun, and the rest is pretty self-explanatory. As always, if you have any questions, comment!