My son chose to be a cyborg this year and so I began to research. I had been dying to try using foam as a medium so this gave me a perfect excuse. I bought the pvc foam from a swap group, 12 blocks for $7.
I then drew out a sketch of what I wanted the armor to look like. Cut it all out from poster board, traced it out on the foam and then cut that out. I laid out all the pieces (only doing one part at a time as to not get confused) It was kind of like doing a puzzle, bit by bit. I used a heat gun to shape the foam and then hot glued the pieces all together. I also used his shoes to shape out the boots so that they could slip right in and he could walk around with no problems.
In between, I made sure to try it on my son and fit it to him to make it comfortable. I added velcro and snaps to the pieces that I wanted to attach together but could still allow him movement, like sitting down comfortably. I reinforced it all with ALOT of hot glue!
I also added elastic so that it would fit more snug to his body. I purchased a morph suit to go under the armor which provided a smooth and secure surface.
I then covered all the pieces in a layer of water/white glue to give it a bit of an extra shine and help hold all the pieces together. I did that twice.
After everything was dry, I spray painted all the pieces with a dark shimmer silver– the brand was meant for plastics-the other brands were too runny and wouldnt stick to the foam. I also sprayed the underside so that the colored foam wasnt as bright. I then used a metallic blue acrylic and painted various places to give it a splash of color.
We did numerous tests of walking around, going up and down stairs and walking outside to make sure that the costume would hold up and be comfortable for all day Halloween.