Im building a neckarmour piece(gorget) and wanted to share on instructables, to my surprise there is not a single one for neck armour so here's the first. For the decorations in the center you can check out http://www.instructables.com/id/etching-large-metal-items/ .
Step 1: Tools and materials
clamps(if you need them to secure the metal for sawing)
some drillbits(the size of the rivets)
sandpaper(i used a range of 240 -600 gritt)
boltcutters or hacksaw
grease or oil(i used silicon spray)
anvil(or something hard like a barbell)
gloves(my hands are full of small cuts so gloves are recommended)
eye protection(recommended,but I already wear glasses so there's a smaller chance of anything getting in my eyes)
8 large nails(rivets)
8 washers(same inside diameter as the large nails)
2 straps with beltbuckles(from a watch or thin belt, I got mine from a hobbystore)
a box of small nails(rivets)
Step 2: Design
First of take a look around the internet to get an idea for your design, I googled; neck armour, neck armor, gorget. My design consists of a front plate and a backplate, both have reinforcements around the outer edge. The front and backplate are connected with 2 small straps on top of the shoulders.
When you decided on a style draw a rough shape onto your cardboard in pencil and cut it out. Once cut out fold it in two so you can cut it symmetrically. Try it on now and again to make sure it fits.