Step 1: Materials and PEPAKURA!!!!!!
Thick paper/board (a4)(make sure it fits in your printer, haha)
Clear cast resin (two part)
Plaster of Paris (or if you have more budget, body filler)
Sculpting tools (I actually only used cutters, small files because I didn't have pro sculpting tools with me)
Matte spray finish
Brown and yellow water based paints (or just go get your poster color set, or watercolors.)
old worn out brush
paint thinner (depends on what paint you're using)
I'm well aware that not everybody is familiar with Pepakura and 3d modelling, so I'm making it easier for you.
Pepakura is a program that unfolds 3d models so you'll be able to make a real life papercraft model of it.
So I downloaded a model from sketchup community component models and reduced the planes for papercrafting, after then I unfolded it in Pepakura and printed it out on a thick paper. If you've never done this before, every edge of the pieces are numbered, where there's another piece that has the same number on an edge, that means they go together. there's a positive piece and a negative piece, if you can see there are flaps to some edges and to some there isn't. when you find the same numbered ones, you'll have to stick the one with a flap to the back side of the one without a flap so their edges would meet. always keep it front side up, if you get me. if you keep on reversing sides you'll just mess the model up sooner or later.
*Oh! What's that right there? A file! must be the papercraft file! Try it now will you?*
the paper is set to a4. the diameter of the helmet is about 25cm I think