Making a Foam Dart Gun (check Legality in Your State, Ages 18+ Only Please)

This whole project was made at TechShop, a nationwide "Do It Yourself" workshop.
Blow guns are not legal in every state or country.  Please check the legality of completing this instructable before continuing.  These foam dart guns can fire a projectile with extreme velocity.  Only responsible adults should complete this instructable.  Do not shoot darts at people!

To build and use this foam dart gun you will need a buy a few things.
-PVC pipe
-foam darts (this build is based upon Nerf brand whistler darts)
-string or twine
-duct tape
-paint is optional

Very few tools are needed to complete the build.
-some kind of saw (hacksaw will be fine, I will use a vertical band saw in this instructable)
-a dremel tool (sand paper will work as well)

Get yourself some 1/2" inside diameter PVC pipe.  Note that the inside diameter measured with a caliper should be approximately 0.585".  If you are using a different size dart, you may need to change the inner diameter of your pipe.  If you are using a different size dart, measure its diameter (at the widest point) with a caliper.  Allow 0.03" of clearance between the dart and the inner diameter of the tube.

Use a vertical bandsaw to cut your pipe to the proper length.  I have found 17.5" to be sufficient.

Put two small notches in the pipe (one at each green mark) so that a piece of string will fit snugly across the diameter of the pipe.  You can use a hacksaw to create the notch.

Round both of the openings of the pipe.  This is to help stop you from cutting your lips or hands on the sharp plastic.  If you want to paint the gun, now is the time to do it!  Do not get any paint on the inside of the pipe as it may decrease the size of the inside diameter of the pipe.

To help protect you from accidentally sucking a dart into your throat, we will put a piece of string over the mouthpiece hole.  We prevent the string from moving around by putting it into the notch that we created with the hacksaw.  The string is held in place by a piece of electrical or duct tape.

Push the dart into the open end of the tube with the whistle entering the gun last.  Use a stick to push the dart all the way to the bottom of the pipe.  Blow into the end of the tube that is protected by the string to fire the dart.