SRD:Mending

Mending repairs small breaks or tears in objects (but not warps, such as might be caused by a warp wood spell). It will weld broken metallic objects such as a ring, a chain link, a medallion, or a slender dagger, providing but one break exists.

Ceramic or wooden objects with multiple breaks can be invisibly rejoined to be as strong as new. A hole in a leather sack or a wineskin is completely healed over by ''mending. ''The spell can repair a magic item, but the item’s magical abilities are not restored. The spell cannot mend broken magic rods, staffs, or wands, nor does it affect creatures (including constructs).