Water Break Test

A crude test to assess a liquids wetting ability is the water break test. Although not measurably accurate this quick and simple test can give the operator confidence that the consumable being employed provides adequate wetting ability. The water break test may also be used to assess part cleanliness – if the water film separates, a contaminant potentially remains.

A suitable polished metallic sheet is stood vertical and the consumable is sprayed directly onto the surface. If the consumable runs off the sheet as a film of even thickness, then this displays a good wetting ability. If the consumable “breaks” (meaning it splits into individual streams) this is an indication of poor wetting ability.

In the event of an unsatisfactory water break test the cause of the “break” requires further investigation and is usually attributed to one of two potential causes.

• Insufficient wetting ability of the consumable which may be remedied with the addition of more surfactant.
• Inappropriate surface condition, which can be further sub-divided into physical and chemical factors i.e. the surface is too rough or residues like oil/grease are still on the surface due to poor cleaning.

It is advisable that the first course of action would be to assess the surface condition of the sheet before attempting to alter the constituency of the consumable which may lead to other adverse effects concerning the consumables other properties.