Repair

The repair skill allows players to fix their tools and weapons for a cost less than it took to make the weapon or tool. For example, one can repair a pickaxe for only two of the material it was made of instead of crafting a brand new one for three. The repair skill is given solely to Engineers.

Repair
To repair a tool or weapon, simply walk up to any iron block (that's not protected by someone else, given) and right-click on the block. This will remove the necessary materials from your inventory and repair the tool. If the weapon is enchanted, not anyone can repair the tool, but it requires a certain repair level (see Arcane Forging).

Arcane Forging
When repairing an enchanted weapon or tool, there is a certain chance (based upon skill level) that the repair will fail and the weapon or tool will revert back to its normal state. Below are the requirements for being able to repair enchanted weapons, and then the given chances that the repair will "succeed."