Back to basics: Dirt nibs in paint

Sometimes going back to basics can make the difference between a quality repair and a failed repair. Refinishing defects can take many forms and be influenced by many factors, such as the technician, the environment, the product selection, or the equipment maintenance to name a few.  

The acknowledgement of the necessity of a clean environment has improved the reduction of dirt nibs inclusion during the refinishing process. Paint booth maintenance, vacuum sanders, technician role separation, and more, all aid in the reduction of dirt nibs—but do not eliminate them completely. 

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

• Per the I-CAR Canada curriculum, and PPG’s recommendation: “During the refinish process, defects such as dust nibs or other debris in the paint can occur.” 

• Per PPG’s Technical tips on how to make polishing easier, it states that “While no painter wants to buff every job, often times it is necessary to remove minor imperfections from a newly finished repair.” 

• Per BASF’s Fundamental Automobile Refinishing Concepts: “While refinishing automotive panels with zero dirt inclusions is possible in theory, it rarely happens in practice. Following best practices, cleanliness in paint-processing areas and equipment maintenance can minimize this problem and should be followed. That said, in most repairs, some dirt is inevitable. 

You might look at original equipment manufacturer (OEM) production painting and believe dust inclusion does not happen at that level. For example: 

• 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—also known as 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 and polish and finish sand and 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.” 

As demonstrated, dirt nib inclusion can be caused by many factors in a collision repair facility. Dust, dirt, and other debris can be stirred up with air movement, carried in by a painter, dislodged from an air hose, and 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. 

To learn more about refinishing best practices, and dealing with dirt nibs in paint, consult I-CAR Canada’s refinish courses.