When applying penetrant by submerging a part in a penetrant bath, how long should the part remain in the bath?

The correct approach to applying penetrant by submerging a part in a penetrant bath is to keep it in the bath only long enough to ensure that the surface is covered. This method focuses on facilitating effective penetration without unnecessary excess time that could lead to residue buildup or surface drying, which can adversely affect the inspection process.

While it's important for the penetrant to adequately cover the surface, maintaining a shorter immersion helps avoid the issues that might arise from extended exposure, such as solvent evaporation or contamination of the penetrant. The key is to achieve sufficient penetration in a timely manner, which is accomplished with careful attention to the time spent submerged.

Longer immersion times, as suggested in other options, may not provide additional benefits and could potentially complicate the evaluation of results, especially if excess penetrant needs to be removed afterward. Hence, limiting immersion to just what is necessary for coverage is the most efficient and effective practice in this scenario.