How to Build a Pen Gun

Step-by-Step Guide

1. 1

   Step 1: Use a pen that will work.

   Not every pen can easily be converted into a rubber band-slinging cannon.
   
   Find a cheap ballpoint pen that uses a thumb-operated "click" mechanism to extend and retract the tip of the pen.
   
   You also should be able to unscrew the pen somewhere in its middle section for easy access to its contents.
   
   Inside the pen, you should find an ink cartridge (usually clear plastic with a metal tip), a few plastic pieces that make up the "click" mechanism, and a small metal spring.
   
   When finished, the pen gun will launch a custom projectile made from the ink cartridge and an ordinary rubber band.
2. 2

   Step 2: Unscrew and open your pen.

   Remove the ink cartridge.The spring may cling to the plastic of the ink cartridge
   - if so, you may leave it.
   
   If not, look for it in the pen
   - if it is still in place at the tip of the writing end of the pen, shake it out or reach for it with some tweezers. , Gently slide it over the tip of the pen up to the small ridge most ink cartridges have.
   
   The spring will provide extra mechanical power for launching your rubber band projectile. , Insert the ink cartridge point-first.
   
   The ink cartridge should comfortably rest in the plastic housing of the "click" mechanism.
   
   When positioned correctly, the back end of the the ink cartridge should stick out of the pen.
   
   Before inserting the ink cartridge, you may want to drop in a small rolled-up bit of paper.
   
   This can help secure the spring to the body of the pen. , Using clear plastic tape, electrical tape, or duct tape, secure one end of a rubber band to the end of the ink cartridge that's sticking out of the pen.
   
   Make sure the rubber band is firmly stuck
   - if it falls off, you could misfire and snap yourself! , Find a suitable target (never a person or animal) and pull the rubber band back to ready your projectile.
   
   Hold the rubber band parallel to the body of the "gun". , The rubber band should snap forward, launching the ink cartridge towards your target.
   
   Best of all, the projectile is re-usable.
   
   Retrieve the ink cartridge, take aim, and fire again!
3. 3

   Step 3: If the spring isn't attached to the ink cartridge

4. 4

   Step 4: re-attach it.

5. 5

   Step 5: Insert the ink cartridge backwards into the "click end" of the pen.

6. 6

   Step 6: Tape one end of the rubber band to the ink cartridge.

7. 7

   Step 7: Pull back the rubber band.

8. 8

   Step 8: Let go of the rubber band to fire.

Detailed Guide

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