Water—it’s essential for life, but also one of the most destructive elements on the planet. On military ships, the corrosive environment caused by salt water and marine growth can lead to structural weaknesses, as well as logistical and financial inefficiencies. Without the proper ship surface preparation before applying anti-corrosive coating, the coating will not adhere to a ship as well and will prematurely break down.
Surface Preparation Techniques
Preparing a military ship’s surface is a vital part of preserving it. It is also the most important factor in regards to the performance of the protective coatings applied. Several preparation techniques can be accomplished using hand and power tools. Determining the best technique depends on the ship’s substrate and the coating manufacturer’s recommendations. The most common techniques include:
- Hydroblasting: Technicians use high-pressure jets of water to clean a surface and spray off loose paint, salt, dirt, oil and some rust, eliminating the need for abrasives. This technique negates problems caused by dust and spent abrasives.
- Rotary wire brushing: Hard wire brushes remove powder-like rust, but not rust scale that’s attached to the substrate. The brushing may make the surface of rust scale looked polished. Technicians may use wire brushing prior to mechanical de-scaling.
- Rotary power disking: A preparation method that uses silicon carbide disks. There are various disk types and grit sizes, which are effective at cleaning pitted and irregular surfaces.
- Mechanical de-scaling: Technicians use pounding-type instruments or cutting blades to remove thick rust and scale, and partially clean disintegrating brittle scale. De-scaling, however, does not remove the lowermost layer of rust or scale on the ship’s substrate.
- Abrasive blast cleaning: A technique that leaves surfaces rough and well-suited for most coatings. This is a common preparation method that uses compressed air to remove paint, salts, rust, dirt and mill scale. While the technique is effective, it is one of the most common sources of shipyard pollution and waste. Improper blasting techniques may lead to higher levels of salt and contaminants on a ship than before the blasting process.
- Solvent cleaning: Technicians use detergents to remove dirt, oil and grease on a ship’s surface before blast cleaning it. If not used correctly, solvents may thinly spread contaminants on surfaces instead of removing them.
Other surface preparation methods include:
- Dry ice blasting
- Chemical strippers
- Bristle blasting
- Soda bicarbonate blasting
- Sponge abrasive blasting with sponges made from abrasive materials
How Does Temporary Climate Control Benefit Surface Preparation?
In the maritime industry, the weather poses one of the greatest maintenance-related challenges. High humidity and adverse temperatures can delay maintenance schedules and add extra expenses. While you can’t control the weather, you can implement temporary climate control solutions to create the ideal environment for surface preparations and protective coatings.
Temporary climate control solutions ensure that protective coatings adhere to substrates in. With the ability to create the ideal environment and temperatures, the coating life may last longer and reduce respective maintenance costs by up to 20 percent. The use of dehumidifiers improve coating productivity and blasts between shifts, eliminating condensation problems and the need for crews to paint-up each day, which speeds up the coating process.
Maintenance-Related Consequences of Improper Ship Surface Preparation
- Corrosion: Corrosion on military ships will cost the U.S. about $114.5 billion between 2011 and 2016, according to a 2011 article in Bloomberg Businessweek. The Navy and Marine Corps alone spend about $6.2 million a year battling corrosion. Without the right surface preparation, soluble materials (i.e., salt and contaminants left from the improper use of cleaning solvents) may remain under coating surfaces, within cracks. When this occurs, the protective coating may blister and allow salt water to penetrate the ship’s metal surfaces. Corrosion may also occur when two dissimilar metals are in electrical contact with one another. In addition to shortening the lifespan of vessels and prolonging ship maintenance, corrosion can delay maiden voyages, as was the case with the USS Independence in 2011.
- Drag: While hydrofoils and warm hulls help reduce a military ship’s drag, improper surface preparation may reduce their effects. One of the consequences of having a ship in the water for long periods is the growth of algae, barnacles, coral and other marine plants and animals on the bottom of a ship. In addition to increasing the ship’s weight, the sea life increases its drag and maintenance needs, while decreasing fuel efficiency.
- Higher maintenance costs: The war on rust costs the Pentagon $22.9 billion per year, according Bloomberg Businessweek. This amount equals about 55 new F-22 Raptor jets and two new naval aircraft carriers. By using the right surface preparation treatments on its ships and the aircraft on them, the Marine Corps was able to drop its maintenance costs by about $85 million between 2005 and 2008.
Improving Productivity with Effective Solutions
Whether you’re preparing a new vessel or maintaining one in dry dock, each surface preparation step and protective coating of paint count. Using temporary climate control system and earth-friendly ship surface preparation services, Polygon creates a controlled environment that’s conducive to continuous work and the optimal curing of surface coats. Call today to learn how Polygon can help ensure coating performance, regulation compliance and cost reductions.
Photo by Official U.S. Navy Page via CC license