Hi Alessandro, I like your name, I love italy (FROST WANT VESPA)
Anyways, After making your army from 110lb cardstock, all you do is buy 2 cans of resin and 3 sheets of fiberglass cloth which comes in 3x3 square foot sheets.
1. Resin the outside of the armor lightly doing half of one side and letting in dry in the sun.
2. once dry, resin the other side of the and wait for that to dry in the hot sun.
3. once the outside in resined with 1 layer, resin the inside with 1 layer, let that dry.
4. take some fiberglass cloth, and some school glue, the white glue you use for crafts and shcool stuff.
5. Apply the glue all over the fiberglass peices you cut from the sheet, dont glob it on, but put it lightly on.
6, place it where you want the fiberglass to go and push in and make the cloth form around the edges and corners.
7, once done let that dry for 10 minutes or so, then resin over the cloth, SOAK it, you want the cloth to look clear, you dont want to see shiny silver, you want to see the color of resin go through the fiberglass cloth. ( You use lots of resin when coating over the fiberglass. )
8, once dried after 1 hour or 2 hours, cut off any fiberglass that sticks out of the peice/helmet.
9. Paint, detail, add visor, have fun.
P.S. Do you own a vespa? the Classic px's are nice, I'm buying one soon.