I've been building a n IM MK6 costume from foam, using the Robo Pepakura files. I've completed most of the upper half so far. Note that the mannequin doesn't have very human proportions - he's stick thin, legs are too long for the body and he has moulded hair so the helmet is slightly too high:
You'll notice that the pieces don't really look like foam, and this is how I did it:
The original pieces are made from Plastazote LD45 foam and hot glue. I cut out all the Pepakura templates and simplified some into bigger pieces. Plastazote foam can be stretched and bent with heat, so most of the cuts in the original templates that make contours can be ignored. I also made some different cuts between the templates, in the chest plate for instance, to put the lines/detail in the right place:
They are then sealed with about 3-4 coats of PVA which dries clear:
PVA is also water soluble - I've done a couple of tests with 'Plastikote Super Primer' which appears to bite into the PVA and stick fast, and also remains slightly flexible. The pieces are a lot more rigid once the PVA is applied anyway - I'm almost tempted to make moulds from some of the parts and cast them in fibreglass so they can be sanded and made perfect.
More to follow as I make the pieces...