Professional and hobby armor makers meet on The Armour Archive Web site to discuss their work and the armoring craft in general. Whatever you want to know about armor, these folks know the answer. Their FAQ and essays are very valuable. So is their library of patterns.
Sometimes they discuss topics the same way they shape metal -- hammer and tongs. Topics that are sure to set the dogs barking are whether plastic armor is worth having, and whether Indian import armor is wrecking the market for local craftsmen. This is about the only link anywhere on this site where you might find strong language, so be warned.