 Ideally, this would be done by pouring in molten lead, allowing it to set, and hammering it tightly with a caulking tool.If this was not possible due to position or some other constraint, the joint could alternatively be filled with lead wool or rope, which was forcibly compacted one layer at a time.This labor-intensive technique was very durable if done properly, but required time, skill, and patience for each joint to be made up.