How long until a surgical wound usually stops weeping?

Varies: It usually depends on the size of the wound. Larger wounds will take more time to heal. Also, everybody heals at different rates. Younger healthy people tend to heal faster than older weaker people. As long as the weeping is just clear fluid. If it is thick and pustular and the wound looks red, it may be infected and will not stop weeping until treated.

A few days : Wounds after operation should generally stop oozing fluid and/or blood within a few days at most. If it continues longer than that, keep a dry gauze pad on top to wick out the excess fluid. If it looks creamy, it is probably infected. In any case, if you think something isn't right, see your surgeon asap.