5 Minutes to a Better Surface Profile
Achieving the optimal surface profile for a project—a crucial component of coatings success—is the focus of the newest installment in the PaintSquare Video Learning Center series.
"Surface Profile" is one of 19 videos in the original instructional series, which explores multiple aspects of protective coatings work.
Created and narrated by experts at KTA-Tator Inc., the series of concise videos covers a wide range of topics, from quality-control and health and safety issues to basics on the proper use of coatings instruments.
Anchoring a Coating System
In this video (5:05), KTA's William Corbett discusses the many factors in obtaining the correct surface profile and how it enhances coating adhesion.
Whether using abrasive blasting or power tools for surface preparation, accurately assessing the profile depth for a project specification is "paramount" for successful coatings, Corbett says.
The discussion includes types and sizes of abrasives, types of power tools, and other factors in profile depth.
"While an inadequate surface profile depth may not properly anchor the coating system, and disbonding may occur, an excessive surface profile may cause rogue or unusual peaks to protrude above the coating film, causing pinpoint rusting and accelerated corrosion," Corbett says.
Measuring Depth in the Field
While a microscope is the most accurate way to measure depth, Corbett notes that this is not practical in the field or shop.
Three methods that are field-friendly are the visual surface profile comparator, surface profile depth gauge and replica tape. These methods are covered in ASTM D4417 Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel.
Both inadequate and excessive surface profile can affect a coating system.
However, Corbett points out that while the standard provides guidelines for how many readings are required to determine an average, it does not address the number of areas that should be measured.
To determine whether a profile conforms to its project specifications, Corbett says to use SSPC-PA 17, Procedure for Determining Conformance to Steel Profile/Surface Roughness/Peak Count Requirements.
PaintSquare expects to present a new Learning Center video from the series every two weeks. Future topics in the series include:
The full series will be available free in the PaintSquare Video Learning Center.