Step 11: Attach Nose Cone to Body
Finally, turn the nose cone over and fill it 3/4 of the way full with hot glue. Be careful here, so that you don't burn yourself. The paper will get warm, but it shouldn't get too hot to hold.
Now, take the rocket body and insert the top (sealed) end into the hot glue, pushing it down so that it sits snugly in the nose cone. Hold everything in place for a few seconds until the glue sets, so that nothing gets misaligned.
Once the glue cools, your rocket is finished.
To fire the rocket, simply insert the pen barrel about 2/3 of the way into the rocket, hold the barrel between your thumb and forefinger and blow hard. Alternately (this works much better, actually), stick the launcher onto an air pump hose and give it a blast to watch it really fly!