As implied in the DMG, only masterwork weapons and armor can receive enchantments.
In the Xaeyruudh campaign, the strength of the enchantment a weapon or piece of armor will accept is dependent on the amount of care that was taken in its forging, as summarized under Masterwork Items.
In the Xaeyruudh campaign, there are several "levels" of masterwork. Masterwork weapons do not simply cost an extra 300 gold pieces and give a nonmagical +1 modifier to attack rolls. Masterwork armor does not simply cost an extra 150 gold pieces and give a –1 modifier to armor check penalty.