A good penetrant must do all of the following except?

A good penetrant must do all of the following except?

• A. Evaporate very rapidly
• B. Enter small defects
• C. Be easily removable
• D. Be compatible with the penetrant

Answer: (A)

In liquid penetrant inspection, the penetrant must be able to seep into tiny surface-breaking defects by capillary action, be compatible with the developer and the overall system, and be easily removable so that surface residue doesn’t obscure the indication. It should have just enough volatility to be applied and removed cleanly, but not so volatile that it evaporates rapidly. If it evaporates very quickly, it won’t stay in the defects long enough to reveal them, and the indication can be weak or missed, reducing sensitivity. Therefore rapid evaporation is not a desirable property of a good penetrant. The other requirements—entering small defects, easy removability, and compatibility—are essential for reliable results.

In liquid penetrant inspection, the penetrant must be able to seep into tiny surface-breaking defects by capillary action, be compatible with the developer and the overall system, and be easily removable so that surface residue doesn’t obscure the indication. It should have just enough volatility to be applied and removed cleanly, but not so volatile that it evaporates rapidly. If it evaporates very quickly, it won’t stay in the defects long enough to reveal them, and the indication can be weak or missed, reducing sensitivity. Therefore rapid evaporation is not a desirable property of a good penetrant. The other requirements—entering small defects, easy removability, and compatibility—are essential for reliable results.