Actually came here to suggest Stabbity's Crescent Rose scythe tutorial but it looks like she's got that covered!
As for the expanding foam, cover it in a layer, maybe two, of paper mache, then a layer of paper clay, and then sand it down to the right surface texture if there are any unsightly bumps. You can then paint over the paper clay!
SacAnime Summer 2014
Friday: Kraehe (Swan Lake variation) (Princess Tutu)
Saturday: Satsuki Kiryuin (awakened Junketsu) (Kill La Kill)
Sunday: Kraehe (rehearsal outfit) (Princess Tutu)
Mitsuki Nase (Kyoukai no Kanata) (30%)
Satsuki Kiryuin (Kill La Kill) (20%)
You can call me Meg.
I like RoosterTeeth, indie music and poetry, and American Spirit menthols.