Directions:

Start by gathering all supplies and cutting pieces to size.  You can use a hack saw to cut the pipe. Be sure to use ABS pipe instead of PVC. This makes the gun last longer because hair spray and other chemicals do not eat away at ABS pipe. ABS is also not affected by heat.

    Take the 1 foot piece of 3 inch diameter pipe and glue on the 3 inch to 1 inch reduction fitting with ABS or PVC glue (be sure the glue matches the type of pipe you are using). Now you should take the 3 foot piece of 1.5 inch pipe and glue it to fitting.

     Now move on to the igniter. I recommend you go to wal-mart and get a lantern lighter from the camping supplies, they are about $3.00. Drill the appropriate size whole, slip it in, and tighten the nuts. You may need to put some hot glue or caulk around it to make it air tight.

   Next take the 3 in threaded female fitting (Is that what you call it) and glue it in place in the back of the gun. Let all the glue dry completely for at least 6 hours. (I recommend 24.)

    The last step is shooting spuds! Take a potato and twist on the top of the barrel so the excess is beginning to be cut away. Now flip the gun upside down and ram it into the ground driving the potato into the barrel. Take  a broom stick, golf club, or hockey stick and ram the potato 3 quarters of the way down the barrel.   Take a bottle of hair spray (I recommend this for the first launch) and spray it into the combustion chamber for a few seconds.  Replace the cap and now your gun is loaded. Be very careful! These guns are very powerful and could really hurt someone! Aim the gun into a large field,  flick the lantern flint and laugh for hours.

Finished Product:

Note: The spud gun pictured has a Y adapter shown between the combustion chamber and barrell where the lantern flint is mounted. This is optional.