Durability is the stat that ends a weapon. This is the only thing that puts it back.
Why it matters more than sharpening
Every SLC weapon carries sharpness and durability, and only one of them is forgiving.
Sharpness caps your damage and can be ground back at a sharpening stone as often as you like.
Durability falls as you use the weapon and never recovers on its own. At zero the weapon breaks permanently — there is no repair from that point, no salvage, and no way back except buying or crafting another.
Keep a weapon repaired and it lasts indefinitely. Ignore the number and you will lose the thing eventually, however sharp you kept it.
Left-click. Do not right-click and sit
As with the sharpening stone, right-click → Sit will seat you and start nothing. Left-click so the SL Colonies experience seats you properly.
The weapon goes on the table
This is the step people miss: the weapon must be off you and on the bench, not in your hands.
Detach it, then drag it from your inventory onto the table. It picks itself up and moves to the right position on its own.
Repairing
Left-click the bench and small rocks begin appearing across its surface.
Click each one before it disappears. Every hit raises durability. Every miss raises nothing. They come fast — deliberately — and some are faster than others.
Keep going until the bench tells you the weapon will not go any higher. That is maximum durability. Stand, pick the weapon up, and re-attach it.
What is worth repairing
A slaughter knife is built for one animal rather than a campaign and is deliberately fragile. Weapons made by a high-level smith carry far more durability to begin with, which is exactly what makes them worth maintaining.
Where it sits
One of the three benches in the Weapon Kit, alongside the Sharpening Stone and the Practice Dummy. It is sold on its own too.
The product page is here: Weapon Repair Bench — SL Colonies