When must a welding portion bag that has been opened be used?

The correct response highlights the importance of maintaining the integrity of a welding portion bag once it has been opened. When a welding portion bag is opened, it exposes the materials inside to the environment, which can lead to moisture absorption and contamination. Therefore, using the contents within the same day ensures that the quality and effectiveness of the welding materials are preserved.

If the materials are not utilized promptly, their performance could be compromised, resulting in potential defects in the weld or other issues during the welding process. This practice reinforces safety and quality standards in welding operations, allowing welders to achieve the desired results without risking the integrity of their work.