How are WW penetrants tested for water tolerance?

• A. By heating to a high temperature
• B. By adding water to penetrant and noting cloudiness or gelling
• C. By measuring viscosity at room temperature
• D. By mixing with emulsifiers

Answer: (B)

Testing water tolerance for water-washable penetrants focuses on how the liquid behaves when it mixes with water. The standard method is to take a sample of the penetrant and add water, then observe whether the mixture stays clear or develops cloudiness or forms a gel. If the mixture remains clear, the penetrant has good water tolerance and will behave as expected during the water-wash step without losing penetrant film or creating residues. If cloudiness or gelling appears, it signals poor water tolerance, meaning the penetrant may not perform reliably when exposed to water wash.

Other options don't measure this interaction directly. Heating the penetrant would alter its chemistry rather than test its stability with water. Measuring viscosity at room temperature doesn’t tell you how the penetrant reacts to water in real washing conditions. Mixing with emulsifiers tests a different property related to emulsification behavior, which is not the same as the basic water tolerance of the penetrant itself.