Back-To-Basics: Dirt Nibs In Paint

Sometimes going back-to-basics can make the difference in a quality repair and a failed repair. Refinishing defects can take many forms and be influenced by the technician, environment, product selection, or equipment maintenance to name a few. Let’s look at dirt nib inclusion during the refinishing processes.

There has been improvement in the reduction of dirt nib inclusion during the refinishing process due to acknowledging the necessity of a clean environment. Paint booth maintenance, vacuum sanders, technician role separation, paint suits, etc. all aid in the reduction of dirt nib inclusion but do not eliminate them completely.

When reviewing paint maker information and I-CAR courses, you will see the acknowledgement of dirt nibs and the reality of not being able to eliminate them.

• Per I-CAR curriculum: "During the refinish process, defects such as dust nibs or other debris in the paint can occur."
• Per PPG Technical Tips: Making Polishing Easier With These Best Practices: "While no painter wants to buff every job, often times it is necessary to remove minor imperfections from a newly finished repair."
• Per BASF Fundamental Automobile Refinishing Concepts: "While refinishing automotive panels with zero dirt inclusions is possible in theory, it rarely happens in practice. Following best-practices, for cleanliness in paint-processing areas and equipment maintenance can minimize this problem and should be adhered to, but in the overwhelming majority of repairs, some dirt is inevitable."

You might look at OEM production painting and believe dust inclusion does not happen at that level.

• In the BMW 2023 ColorSystem Manual, BMW states: "During production the vehicles are painted in a "clean-room" environment to minimize dirt inclusions in the finish. Although the environment is considered ultra-clean, dirt inclusions are still unavoidable. Every vehicle undergoes vehicle de-nib (fine sanding) and polish procedure to remove dirt inclusions at the factory to ensure the highest level of quality paint finish and appearance."
• Nissan/Infiniti has a De-Nib & Polish And Finish Sand & Polish position statement. Per the document: "After refinishing any outer panel, it may be necessary to nib sand (or de-nib) any particles found within the final finish followed by polishing affected areas...Nissan also completes these same processes in the manufacturing environment due to intrusive dirt or debris found in the production environment."

In a collision repair facility, dirt nib inclusion can be caused by many factors. Dust, dirt, and other debris can be stirred up with air movement, carried in by a painter, dislodged from an air hose, and even become attracted to a panel with static electricity. Following industry best practices, paint maker instructions, and standard operating procedures will aid in the reduction of dirt nib inclusions but there is no conceivable way to eliminate them completely.

Additional I-CAR Collision Repair News you may find helpful:

• Back-To-Basics: Environmental Considerations For Refinishing
• I-CAR Repairers Realm: Controlling Static During Refinishing - Now Available
• I-CAR Repairers Realm: Spray Booth Cleaning And Prep/Paint Defect Removal - Now Available

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Related I-CAR Courses

Course Controlling Static in the Refinish Process

Course Refinish Defects Correction

Course Understanding Refinish Defects - Part 1

Course Understanding Refinish Defects - Part 2