Penetrant testing (PT) is a method that is widely applied to check welded joints on structures; this method reveals surface-breaking defects of the welded joint.
The penetrant (usually red) is applied on previously cleaned and degreased surface.
After penetration into a possible crack, the penetrant is removed in an appropriate way (cleaning agent, dry cloth). After surface drying, the developer is applied (usually white), which draws the penetrant from defects out onto the surface to form a visible red indication.
