Massachusetts Plumbers Journeyman Practice Exam 2026 - Free Plumber Journeyman Practice Questions and Study Guide

The correct answer is based on the behavior of molten lead and the properties of oakum in plumbing joints. After the installation of a joint where oakum is used to create a seal and molten lead is poured over it, there is a critical period during which the lead remains workable.

The recommended time to caulk the joint along the inside and outside edges is typically around four minutes after installation. This timeframe allows for the lead to properly set while still being in a malleable state, providing the opportunity to create a strong seal before it cools and hardens completely. If too much time passes, the lead may solidify, making it difficult to smooth out or shape the caulking effectively, which can lead to leaks or weak points in the joint.

It's essential to adhere to this time window to ensure the integrity and functionality of the joint, as well as to prevent future issues with plumbing performance.