This is my first costume build. It's a simplified version of the armour used in the video game Gears of War 3. I made it using foam matting, similar to camping ground mats but a bit thicker. I made a few templates with card then cut matching pieces out of the foam. It was all attached together using a hot glue gun.
The great thing about using foam mats is that you can use a heat gun to bend and shape them to get something that fits the contours of your body.
To get the armour to look 'battle damaged' I used a pretty good trick. All I did was spray silver spray paint onto the rough side of a sponge and scraped away at each of the edges. I used a Dremel to add extra detail. This was especially good for creating holes that look like screws.
I glued some velcro patches on the straps under the arms for easy removal ...et voila, one simple Gears of War C.O.G. Armour. Maybe I will try something more elaborate next time. Such as a full set of armour from the Mass Effect series.