Liquid Penetrant Inspection

Liquid penetrant inspections provide a low cost option for locating surface cracks too small to be seen by visual inspection. An ultraviolet reflective liquid is first sprayed or wiped onto the surface of the material. After a period of time, the liquid will enter cracks via capillary action. The excess liquid is wiped from the surface and a powder is then applied. The powder draws the liquid back out of the crevices to the surface. An ultraviolet light is then used to illuminate the surface revealing the remaining liquid. The area of the liquid will be larger than the crack size.