This paper details a novel surface preparation process that is suitable for Duplex coating of galvanized steel intended for a variety of atmospheric and embedded service applications. It provides all the properties necessary for excellent coating performance and longevity, including high adhesion, excellent resistance to cathodic disbondment, and resistance to ingress of water, without the drawbacks associated with abrasive blasting, the traditional surface preparation method.
The purpose of surface preparation is to get a required adhesion between steel and the coated film. Adhesion is a significant factor for the suitability and life of protective coatings in corrosive surroundings. In the shipbuilding industry, air blasting with round blasting nozzles is common practice for achieving the productivity and proper surface profile. Generally, the round blasting nozzle cannot evenly spread the abrasive material on a steel surface compared with a rectangular nozzle.
Have you ever wondered about the huge amount of money you spend in abrasives, logistics, recovery and cleaning of abrasives and the great amount of resources used during a project in the stage of surface preparation when you have a project for Maintenance of Storage Tanks? well, with this presentation you will learn about a great new technology available in the American market for this specific activity.
At present multiple standards on blast-cleaned surfaces are in use depending on region and specifications of the project. However, most standards are relatively clear on the description of a surface some overlap each other. These overlaps are often considerate as the norm for the most comparisons between ISO and related documents, however, sometimes are significantly off. Some of these documents will be highlighted to compare the results and their impact on the coating job.
In early 2009 the City of Sunnyvale in Northern California put out to bid a repaint of three five‐million gallon water tank exteriors. The tanks existing coatings qualified as leadbased paint with average concentrations of 120,000ppm or 12% lead. The three tanks were successfully abrasive blasted to an SSPC SP‐10 and recoated with a zinc/acrylic system without erection of an SSPC Guide 6 Type 1A enshrouding containment. This paper tells the story of how this was done successfully using standard but not often seen work practices, even though the project was right next door to an elementary school and multi‐family residential developments and so had to perform to the strictest levels of environmental standards.
This paper presents results of multiple test programs that have been performed to determine the effectiveness of recyclable encapsulated abrasive media to remove chlorides during surface preparation. Tests published in 2002 concluded that this technology consistently achieves significant reductions of chloride levels in comparison to those achieved with conventional abrasive blasting.
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.
Using dehumidification in shipyards has been a widely accepted practice for three decades. A lot has been learned and techniques have become much more sophisticated but the basic goal of preserving the blasted steel and creating the right conditions for coatings application remains the same. This paper discusses how various combinations of desiccant dehumidification, heating and cooling equipment have been utilized properly and some examples of when things did not work out so well.
Protective coating systems provide the primary corrosion protection for assets in sea water. Protective coating systems are defined as a specific combination of surface preparation and coating material applied under specified conditions to a specific structure. Over the past many years, the paint industry has focused considerable resources toward the formulation, performance testing and fine tuning of coatings materials.