As per the usual, be smart when building anything that shoots, bangs, or catches fire. I am not responsible for any silly choices! Always use appropriate safety gear and know how to operate any equipment you may use.
Step 1: Parts List and Assembly
1x 6" length of 1" pipe
2x 1" to 1/2" reducing bushings
2x 1/2" T-JUNCTION s
1x 1/2" to 1/8" reduction bushings
1x 1/8" tire valve
4x 1/2" Nipples
1x 1/2" by 3" pipe
1x 1/2" cap
1x 1/2" Ball valve
1x 1/2" to 3/8" reduction bushing
1x 3/8" Pressure Gauge
A whole lot of Teflon tape
A vise, though this can be optional
A crescent wrench
I neglected to photograph the assembly of this project, but outside of teflon tape and rotating parts clockwise there is not much to show.
My airtank for this was assembled out of 1 inch by 6 inch threaded pipe, capped on either end by a 1" to 1/2" bushing. On one end, there is a tire valve and corresponding 1/2" brass bushing. I found that I could not located these tire valves at the big box hardware shops where I found the rest of my kit. I found these at a local auto parts shop.
On the other end, a 1/2" nipple leading to a 1/2" T-junction. the first T-junction is capped with a 1/2" to 3/8" bushing, and a pressure guage after that.
The nipple/ T is repeated again with a small section of 3" by 1/2" pipe and corresponding cap for a convenient handhold.
On last nipple, connecting to a 1/2" ballvalve threated on either end so that I can swap out any lenght of 1/2" pipe for a barrel. Pictured is another small length of 1/2" pipe, suitable for a single Nerf dart with some electrical tape around the head to ensure a snug fit.
Good luck, have fun, and be safe!