Menu
Search
Filters
Close
Menu

Celebrate World Corrosion Awareness Day with 20% off eCourses and eBooks with code WCAD2024 at checkout!

Effect of Feathering on Coating Performance

Effect of Feathering on Coating Performance
Available for download

Feathering is the process of tapering or blending-in an existing intact coating in preparation of applying a new repair coating. This industry common practice is intended to ensure good adhesion of the repair coating to the legacy coating, and to provide a seamless aesthetic transition for areas where maintenance painting is performed. There are no industry standard requirements for performing feathering, resulting in most specifications having their own unique definition. 

Product Number: 51219-181-SG
Author: Patrick Cassidy, Michael Kibler
Publication Date: 2019
Industries: Military , Coatings
$0.00
$20.00
$20.00

Feathering is the process of tapering or blending-in an existing intact coating in preparation of applying a new repair coating. This industry common practice is intended to ensure good adhesion of the repair coating to the legacy coating, and to provide a seamless aesthetic transition for areas where maintenance painting is performed. There are no industry standard requirements for performing feathering, resulting in most specifications having their own unique definition. The U.S. Navy definition for feathering states that intact coating should be feathered to a thirty-degree angle. This definition has caused confusion for both contractors and inspectors performing maintenance work on Navy vessels, leading to extensive rework. Based on comments from waterfront personnel, the U.S. Naval Research Laboratory (NRL) sought to clarify the definition and best practice for performing feathering. While performing the literature review, feedback from industry suggested that feathering may not be a necessary step at all in the coating repair process, and in fact may be deleterious to repair coating performance. NRL designed a test plan to test this hypothesis, which included laboratory testing, an industrial demonstration on a mock ballast tank, and a shipboard demonstration. Multiple repair coatings were tested over various surface preparations (e.g., power tools and spot abrasive blasting) in which feathering was either performed or not performed. The results were consistent across all testing that feathering of the intact legacy coating did not affect the performance of the repair coating. It was also determined during testing through collection of production metrics that feathering added as much as twenty percent to the labor cost of the job. From the testing results, NRL drafted new specification language for the Navy that stipulates feathering shall only be performed in areas where aesthetic appearance of the repair coating system is important. The specification language was also updated to clarify that when aesthetic appearance of the repair coating is important, intact legacy coatings are to be feathered back via a one-to-two-inch width border around the periphery of the bare substrate. These specification changes have two benefits: (1) save the Navy up to twenty percent on labor cost when performing repair work where feathering is no longer needed (e.g., tanks, voids, machinery spaces), (2) provide cost savings by reducing rework when performing maintenance painting in areas that still require feathering (e.g., underwater hull, topside, freeboard).

Feathering is the process of tapering or blending-in an existing intact coating in preparation of applying a new repair coating. This industry common practice is intended to ensure good adhesion of the repair coating to the legacy coating, and to provide a seamless aesthetic transition for areas where maintenance painting is performed. There are no industry standard requirements for performing feathering, resulting in most specifications having their own unique definition. The U.S. Navy definition for feathering states that intact coating should be feathered to a thirty-degree angle. This definition has caused confusion for both contractors and inspectors performing maintenance work on Navy vessels, leading to extensive rework. Based on comments from waterfront personnel, the U.S. Naval Research Laboratory (NRL) sought to clarify the definition and best practice for performing feathering. While performing the literature review, feedback from industry suggested that feathering may not be a necessary step at all in the coating repair process, and in fact may be deleterious to repair coating performance. NRL designed a test plan to test this hypothesis, which included laboratory testing, an industrial demonstration on a mock ballast tank, and a shipboard demonstration. Multiple repair coatings were tested over various surface preparations (e.g., power tools and spot abrasive blasting) in which feathering was either performed or not performed. The results were consistent across all testing that feathering of the intact legacy coating did not affect the performance of the repair coating. It was also determined during testing through collection of production metrics that feathering added as much as twenty percent to the labor cost of the job. From the testing results, NRL drafted new specification language for the Navy that stipulates feathering shall only be performed in areas where aesthetic appearance of the repair coating system is important. The specification language was also updated to clarify that when aesthetic appearance of the repair coating is important, intact legacy coatings are to be feathered back via a one-to-two-inch width border around the periphery of the bare substrate. These specification changes have two benefits: (1) save the Navy up to twenty percent on labor cost when performing repair work where feathering is no longer needed (e.g., tanks, voids, machinery spaces), (2) provide cost savings by reducing rework when performing maintenance painting in areas that still require feathering (e.g., underwater hull, topside, freeboard).

Product tags
Also Purchased
Picture for Coatings + Proceedings 2021-ALL Papers

(Coating Application, Types & Characteristics) Use of Duplex Coating Systems for Protection of Structural Steel

Product Number: 15-COAT_DEC21
Author: William D. Corbett
Publication Date: 2021
$20.00

The use of duplex coating systems (hot dip galvanizing or thermal spray coating with one or more liquid-applied coatings) for long term protection of structural steel is becoming more mainstream in many industries. This paper describes the advantages of employing duplex coating systems as well as some important considerations for designers prior to specifying their use. It also highlights an ongoing initiative to help agencies more efficiently and effectively use duplex coatings on steel bridges by developing guidelines, standards, and other materials.
Picture for Coatings + Proceedings 2021-ALL Papers
Available for download

(Inspection) Coating Condition Assessments: The First Step in Fighting Corrosion on Aboveground Sto

Product Number: 53-COAT_DEC21
Author: Adam G. Beers / Lake H. Barrett, Jr.
Publication Date: 2021
$20.00

Being proactive and performing scheduled coating condition assessments on above ground storage tanks to prevent corrosion is of utmost importance to protect assets. Undetected corrosion can result in product contamination, section loss, create compliance issues resulting in fines levied by governmental agencies, and increase costs of asset replacement. Planned and detailed coating/lining condition assessments can help a tank owner realize the current condition of their assets and maximize life expectancy.
Coating Performance Over Partially Blasted Surfaces
Available for download

Coating Performance Over Partially Blasted Surfaces

Product Number: 51219-180-SG
Author: Patrick Cassidy, Peter Ault, Cameron Miller , Colton Spicer
Publication Date: 2019
$20.00

Common methods of maintenance painting either involve complete removal of existing paint (SSPC-SP 10) or localized preparation using power tools (SSPC-SP 3). Sometimes an intermediate level of surface preparation may be performed by allowing intact tightly adherent coating to remain. Abrasive blasting may be used to prepare either localized areas, or to partially prepare the entire surface, allowing well-adhered aged coating to remain. 
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support