Abrasive blasting uses various materials to strip imperfections, paint, rust and other contaminants from a surface. It’s an important step in surface coating preparation, as it cleans a substrate and creates a surface that will hold a protective coating. Blasting takes the place of more labor-intensive cleaning methods like wire brushing or sanding, and can speed up the surface preparation process by up to 75 percent.
Abrasive Blasting Methods
- Bead blasting: Uses glass beads to remove surface deposits; it works well for cleaning fungus, paint and calcium deposits
- Wheel blasting: An airless blasting technique that uses centrifugal force to shoot abrasives against a surface without the help of a propellant
- Hydro blasting: Also known as water blasting, this technique uses high-pressure water to remove paint, debris buildup and chemicals
- Wet abrasive blasting: Uses cold or hot water to remove grease, dust and hazardous materials; a user has the ability to add detergent to the water to improve cleanliness levels
- Dry ice blasting: A technique that uses air and dry ice to dislodge items from a surface, as well as decontaminate; because the dry ice sublimates, cleanup is minimal
- Micro-abrasive blasting: Also call pencil blasting, this dry blasting technique uses a small nozzle that directs a fine stream of abrasive media to a targeted area; this method is suited for detailed work
- Bristle blasting: Instead of using a blast media, this technique uses a high-carbon rotary steel brush that prepares a surface and makes it coarse
- Automated blasting: An automated blasting process done within a chamber
- Dry abrasive blasting using compressed air: Compressed air is used to propel the abrasive through rubber hoses and a blast nozzle. This is the most common type of abrasive blasting and is used on fixed structures and field work.
Media Used for Abrasive Blasting
- White aluminum oxide: A sharp, reusable and durable abrasive that cleans and penetrates metal; technicians often use it to prepare a metal surface for painting
- Aluminum oxide grit: A standard blasting media used for grinding, polishing, surface cleaning and surface coating preparation
- Glass beads: Reusable glass media that’s lead- and silica-free to clean and polish metal without causing dimensional changes
- Crushed glass grit: An abrasive made from recycled glass bottles that’s used to remove coatings from materials like coal tar, epoxy, paint, vinyl and polyurea
- Acrylic: A gentle abrasive used to strip sensitive surfaces
- Corncob grit: A reusable, biodegradable, organic media made from corncobs to clean and remove surface contaminates
- Pumice: An abrasive made from lightweight volcanic rocks that’s ideal for less aggressive operations
- Walnut shells: Blasting media made from walnut shells that cleans and polishes a surface without marring, scratching or etching it
- Silicon carbide grit: The hardest blasting media available; used for etching stones and engraving glass
- Steel grit: Used when aggressive cleaning is needed on steel or foundry metals; also used for metal surface coating preparation
Benefits of Abrasive Blasting for Surface Coating Preparation
Abrasive media is generally inexpensive and many types are reusable. Blasting offers additional economic advantages because it efficiently cleans surfaces better and faster than traditional techniques. It’s also effective at removing rust on metal surfaces.
Abrasive blasting prepares surfaces for coating applications effectively. During the process, it’s important to keep temperatures and relative humidity levels low using temporary climate control solutions to eliminate excess moisture that could hinder the protective coating’s application and drying. Temperature and humidity control is particularly vital when preparing metal surfaces, as the bare metal’s exposure to the environment makes is susceptible to oxidation.
Polygon is a leader in temporary climate control solutions. Whether you’re preparing a ship or cleaning mechanical components in a factory, Polygon will help create an environment that promotes worker health and safety, increased productivity and improved coating performance.
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