Developer Powder
Developer powder is a fine, absorbent powder applied to the cleaned surface to draw penetrant out of discontinuities to the surface.
Physical-Chemical Mechanism of Action
Developer powder consists of fine particles with a high surface area. These particles are absorbent and can pick up penetrants like water or fatty acids from the material surface.
Metallurgical Relevance & Risks in Welding
The developer powder helps clean the surface and make discontinuities visible. It prevents penetration of fatty acids or other substances that could affect the weld. If the powder is not applied correctly, overapplication can occur, leading to poor surface quality and possibly cracks.
Workshop Practice & Instructions
1. The surface of the weldment must be thoroughly cleaned.
2. Apply the developer powder from a fine spray can onto the surface.
3. Let the powder sit for at least 5 minutes to absorb the penetrant.
4. After the dwell time, clean the surface with a damp cloth and dry it.