I found the instructable for the Optimus Prime costume and went to town on building my own. I wanted to take it a step further and add his main weapon. Here's how I made it. What you'll need: - 3" cardboard tube(s) - 4" cardboard tube - regular cardboard - Nerf Vortex Vigilon blaster - Hot glue gun/lots of glue sticks - 4" foam brush (handle only) - Spray paint (primer, semi-gloss black, blue)

Step 1: Base/Back End

I used a Nerf Vortex Vigilon blaster for the base gun grip because it was cheap and looked cool. Found a picture online of the ion blaster and just guesstimated measurements. Came out pretty good I think. I got varying sizes of cardboard tubes from work and sliced them to fit over the gun and hot glued them on. The box on the back end is 5" wide by 7" tall by 4" thick.

Step 2: Middle/Barrel

For this, I cut o-rings out of cardboard to slide over and glue onto the smaller tubes to then slide into the larger tubes and glue into place. For the top and bottom add on pieces, I looked at the picture and guesstimated the size and shapes, then measured and cut several same shape pieces out, glued them together and then glued them on. Not seen here on the bottom box, added later, is the end of a foam paint brush. I was going to use a dowel rod, but it was only going to be like 3" so a foam brush handle was the cheaper option and perfect size. I used 3" cardboard tubes for most of the barrel. The back end near the box was a 4" tube. The overall length of the blaster is 37 3/4".