Masking for Electrocoating

Question: Can electrocoat be masked like powder or liquid coatings?


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Can electrocoat be masked like powder or liquid coatings? R.K.


Yes, electrocoat can be masked but provides some challenges and opportunities that are not normally found with liquid or powder coatings. The challenges that electrocoat provides include:

  1. Electrocoats have an inherent desire to get between the masking material and the substrate and the electrical desire to deposit coating under the masking.
  2. Curing metal temperatures of most electrocoats are similar to those of powder coatings, requiring silicon rubber masks or silicon-based adhesives on tape, dots, etc.
  3. Since most electrocoat systems do not require a dry-off oven after pretreatment, masking must start prior to the washer and stay on through the post rinse system.

Advantages of the electrocoat process that may reduce, alter or eliminate masking requirements include:

  1. The coating is so uniform in thickness that the part tolerance might be able to be adjusted for the electrocoat thickness.
  2. The coating is thin enough to provide electrical grounding with self-tapping screws or star washers to cut through the coating.
  3. The coating thickness is thin enough to not require masking of internal or external threads.