General notes on diagnosing cracks in aluminum parts - AH60.00-P-0014-01N

Models 215, 220 

Before and after performing repair work on aluminum components check whether cracks, inclusions or other welding faults are present.

A suitable testing method is the simple color penetration method with which faults starting at the surface or in direct connection with it and which are not visible to the naked eye, are made visible by the color constrast. This method uses the capillary effect of the fine openings in the surface. Died liquids with low surface tension penetrates into these openings and can be identified there with suitable contrast agents.

Usually bright red or yellow green fluorescent colors which can be washed out with water are used as a penetration agent. The penetration agent can be sprayed on or applied with the brush.

During the penetration time, the penetration agent should never be allowed to dry. The smaller the surface faults, the greater the penetration time (approximately 5 to 30 minutes).

The developer then used must have a high absorbency so that the penetration agent is sucked out of the damaged point. This makes the fault visible through contrast in the developer layer. The developing time is analog to the penetration time. As a matter of principle, however, faults can only be found when they are on the surface of the material.

Before applying the cleaner, contrast agent and developer, always observe the safety notes  of the individual manufacturers.

All three diagnostic agents are highly flammable. In addition, the contrast agent poses a health hazard.

Typical damaged patterns using the color penetration process. 

Example of crack diagnosis: 

Inner C-pillar