Board Thread:Wiki Discussion/@comment-71.194.61.18-20131011173147/@comment-23825938-20131011183922

Craftable armors like RocFeathers robes will unlock the +version when you get the regular version to level 35. Then you can craft the +version at armorsmith.

Armors that are NOT craftable, like Sky Guardian, you can only get the plus version from the chance chest.

You can NEVER get a plusversion from fusing two armors together.