Which of the following is NOT a characteristic of an effective penetrant?

An effective penetrant should possess specific characteristics that enhance its performance in detecting surface defects. High viscosity is not desirable in a penetrant because it restricts the penetrant's ability to flow into small cracks and pores. Instead, low viscosity is preferred, as it allows the penetrant to spread easily and enter fine flaws quickly.

On the other hand, low surface tension is crucial because it enables the penetrant to wet the surface effectively, facilitating its entry into tiny openings. The ability to enter fine cracks is a fundamental requirement for a penetrant, ensuring that it can detect even the smallest defects. Additionally, good fluorescent properties are important for visualizing indications under ultraviolet light, enhancing the effectiveness of the inspection process.

In summary, while low viscosity, low surface tension, the ability to penetrate fine cracks, and good fluorescent properties are all key characteristics of an effective penetrant, high viscosity poses a limitation in those critical functions.