Tack welds are used to temporarily hold two pieces of metal together until the final weld can be completed. While tack welds are not as strong as a full welding bead, they can still provide a good amount of strength and support. The key is to make sure that the tack welds are placed correctly and evenly spaced apart. If done properly, tack welds can provide a strong hold that will last until the final welding bead is in place.