This is how to build a Rocket Launcher from Team Fortress 2 for cosplay or to decorate your mantle. This was made at LVL1, Louisville's Hackerspace. (see more at http://www.lvl1.org
) Be sure to check your area for a hackerspace, they're a great place to meet new people, learn new things and get access to awesome tools.
The really awesome thing about this build is at the con you feel like you're in the game. Most prop guns don't show in your field of vision but this thing sitting on your shoulder looks exactly like what you see in game which makes being a solider even more awesome.
4.5" diameter PVC pipe
2" thick insulating foam
0.5" thick insulating foam
24x36" sheet metal
1/8" craft foam
small piece of 1/2" wood (for the handles)
1/8" wood or other solid material
lots of hot glue