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NAVSEA Having Luck with New Coating Removal Method

By Cynthia Greenwood

Each year the Navy generates more than 9 million pounds of grit and paint-removal waste while removing coatings on the steel tanks and voids of its ships. It costs NAVSEA $2.7 million each year to dispose of this waste. The routine corrosion control practice also generates dust and debris that can contaminate other maintenance processes.

Heat induction is much faster than grit-blasting, NAVSEA officials say.

The process of removing coatings on ships using abrasive blasting poses significant health hazards to industrial workers and great environmental risk, according to a 2007 project plan titled Enhanced Coatings Removal Process submitted by the Naval Research Lab (NRL) to the Office of the Secretary of Defense. "It is vitally important that alternative coatings removal processes be investigated ... and adopted to ensure the safety of employees and contractors for the preservation of DoD assets," the plan states.

One such alternative method is known as heat induction technology. Beginning in 2006 NAVSEA officials began testing and improving this technology to remove coatings in ship tanks and voids. While the technology itself is not new, applying it to remove coatings in this manner is innovative. The process involves passing an electrical current through the metallic substrate or paint surface and heating it to several hundred degrees. Heating the coating in this way releases the coating adhesive feature and allows someone to scrape away the bulk coating with a hand scraper, leaving a bare surface.

Heat induction is much faster than grit-blasting, NAVSEA officials say. Because the heat induction process is so fast and effective, the Navy has encountered a few issues of concern. There is potential to overheat the substrate, so NAVSEA and the Naval Research Lab are working with the manufacturer to minimize the risk of damage to the substrate, and the risk of fire. Besides the Navy and ONR, the DoD Corrosion Office is providing financial support for the project.

According to the NRL’s project plan, the technology is promising but greater control of the process "compatible with DoD needs" is necessary to ensure quality assurance and minimize potential damage to the substrate of ship tanks and voids.