Blasting and Surface Preparation
Preparing steel and other surfaces for new coatings often calls for abrasive blasting first, to remove previous paint, mill scale, rust, or contaminants. Experts estimate that as many as three quarters of coating failures occur because of inadequate surface preparation. Abrasive blasting uses a controlled flow of abrasive mixed with compressed air delivered to the surface of the substrate, to clean the surface and leave a profile. The type of abrasive used varies with the job but can be sand or sand substitute, steel grit, garnet and others. Sponge media combined with one of a variety of abrasives available, produces very little dust and can also be recycled. Vacuum blasting is also an option for media capture.
The profile is the angular roughness of the surface which coatings can grab onto-and in general the greater the surface profile-the peaks and valleys of the micro-indentions in the substrate-the better the coating will adhere to it. Following the recommended industry standards for the surface profile of the substrate and the coating system gives the best chance for a successful paint job. Here is a brief rundown of the blasting we perform:
Types of Blasting
Abrasive blasting—combines a pressurized stream of air with an abrasive, which is propelled onto the surface of steel to remove paint, rust, and contaminants. Abrasive blasting can also be used on concrete to remove discoloration and other marks, and on brick and masonry to clean it.
Dry abrasives used in surface prep include sand, sand substitutes, coal slag, steel grit and garnet. Dry abrasives are sometimes combined with a sponge media to reduce dust at the site of the blast, and sponge is recyclable.
Vacuum blasting systems—capture and collect the blast media;
Water blasting—uses water with abrasive, reducing dust;
Bristle blasting—a hand-held power tool that removes contaminants and creates a surface profile using wire belts, typically used for small areas;
Shot blasting—typically used on concrete to remove existing coatings, and dirt;
High pressure water blasting—water only, at high pressure to clean surfaces and create a profile.
We have the people and the equipment to get this job done for our customers. Vulcan Painters has trained blasters who will blast to customer specifications as established by SSPC and NACE. Our Protective Coatings Specialists (PCS) are experts at helping select the best combination of blast specification and coating system for your project.