There's a repair tab in the GUI, however clicking it doesn't change the looks too much. The gun slot is the same as in normal mode, it shows the same gun in both. Text will change from "Gun Assembly Station" to "Gun Reparation/Repairing Station". The renaming position gets replaced by some buttons here.
The first button is simply "Repair", and is clicked by default (these buttons are modes). With this, you'll need to click a component to repair it, and it will repair the item once.
Second button is "Repair all", which will automatically repair as much as possible of the components, and gladly use up the wrench.
If you cannot repair anything, both of these buttons are unclickable.
1 repair = -1 wrench durability, +10/15/20 component durability, depending on how much durability the component has lost.
Old
Guns get worse the more you use them. The "repair" tab in the assembly station is for fixing this. The parts of the gun are only the damaged, and the gun item only shows the most damaged (/durability). All components now have a durability, and the chance of a component losing 1 durability is 10% every shot. For every 5th durability lost, or closer the item is to 0 durability, the chance of the durability decreasing will be 5% greater. There is a chance of the item losing 2x the durability, but that's 2x less the chance. Also applies to 3, 4 and 5. That allows the percent to be over 100 too. (Update: Does anyone understand this?)
When a component lost all it's durability, the gun becomes a "broken gun". It's then not operational, and can only be fixed by replacing the broken component. If the component is not broken though, the wrench restores 10 durability per wrench durability point.
There is no repair tab. However, the default tab has a button in the top-right of the GUI, that has some symbol of repairing (anvil-ish?). Clicking this will enable "repair-mode", where you will repair 10 durability of a component by clicking it. So you will know what you're doing, once you hover an item, the slot will be replaced by a button with the repairing symbol. Clicking that will repair the item (read above for how much).
Connected to #43 Broken Guns.
Repairing
There's a repair tab in the GUI, however clicking it doesn't change the looks too much. The gun slot is the same as in normal mode, it shows the same gun in both. Text will change from "Gun Assembly Station" to "Gun Reparation/Repairing Station". The renaming position gets replaced by some buttons here.
The first button is simply "Repair", and is clicked by default (these buttons are modes). With this, you'll need to click a component to repair it, and it will repair the item once.
Second button is "Repair all", which will automatically repair as much as possible of the components, and gladly use up the wrench.
If you cannot repair anything, both of these buttons are unclickable.
1 repair = -1 wrench durability, +10/15/20 component durability, depending on how much durability the component has lost.