Wiki - Enhancing Arms & Armor
While items made out of normal iron, wood, granite or leather, either crafted or found as loot, lack the special material bonuses applied by using colored versions of the resource, a skilled craftsman still has the ability to enhance the item after the fact.
Plain weapons or armor can be enhanced with special materials using the ‘Enhance’ option on the relevant craft menu. These craft menus are:
Success will add the material’s fixed properties (resource properties) to the item.
This means that once you’ve been lucky enough to find a superior item as loot on a monster, you can seek to improve it by enhancing it with special materials. However, enhancing an already existing item with special materials is difficult.
Only Crafted & Looted, Non-Artifact Items can be enhanced. Imbued Items may be enhanced so long as they meet all other requirements.
Items made with any resource material already can not be enhanced.
Weapons with Level Deeds applied can not be enhanced.
Weapons that have benefited from a Whetstone can not be enhanced.
Failing an Enhancing attempt will cost you some of your materials, but there is also a very good chance of destroying the item. Once enhanced, the item is considered to have been made out of the special material infused into the item, so it can never be Enhanced again.
The inherent difficulty in Enhancing an item works as a balancing factor, the more properties an item has, and the higher the intensity of those properties, the more difficult it will be to enhance, and the higher the chance that the item will be destroyed.
The chance for successfully enhancing an item is increased if you have above GM skill level in the applicable craft skill. A blacksmith’s +60 Ancient Smith Hammer is most desirable for this purpose, but even this will not guarantee success on items that are very powerful already.
You are also required to have enough skill to craft items with the materials you want to enhance with. For example, to enhance an item with Legendary Ingots, you would have to be at or above 130.0 Blacksmithy skill.