US Patent 7552623 Enhanced leak detection dye carrier

A leak detection dye carrier is formed using a two-stage process (53). In a first stage, the dye carrier (52) is saturated with a mixture (54) of a dye powder and an evaporable solvent, such as alcohol. The solvent is permitted to evaporate leaving dispersed dye solids (56) on the dye carrier (52). In a second stage, the dye carrier (52) and dispersed dye solids (56) are immersed in a wet bath (58). The method may be a hybrid of dry and wet systems of placing dye onto a substrate carrier in which the wet bath is a mixture of a dye and a solvent, such as a system lubricant. Alternatively, the immersion of the dye carrier in the second stage may be limited in duration to prevent the dye solids in the first stage from being dissolved.