Aegis has been sandblasting aluminum, stainless steel, hot-dip galvanized steel and other types of steel for over 40 years. Sandblasting aluminum and steel is one of the most effective ways to clean and prepare metal materials for powder coating. Having a clean metal surface that is free of mill scale, rust, oxides and previous coated layers is essential for powder coating. Flawless powder coating results, start with sandblasting.
There are three main benefits of sandblasting:
- Sandblasted Steel and Aluminum material are cleaned
- Sandblasting leaves an anchor profile that increases the bond strength of a powder coat
- Corrosion resistance is increased due to the increased bond strength
Factors to consider when Sandblasting
When preparing to have a job sandblasted, some factors need to be considered to ensure the job is done as efficiently as possible,to save time and cost.
The age and type of previous coatings can have a significant impact on sandblasting. There are certain coatings we are not equipped to remove, such as lead based paints. In these instances it is usually more cost efficient to have the coating stripped at a blast-only shop, and then we can do a quick sandblast to clean up any oxides that have formed after blasting.
Mill scale, or iron oxide, is a hardened surface on hot rolled steel that is formed during the milling process. Mill scale and steel have different electric potentials which result in the mill scale causing rust to form on the surface steel, leading to the failure of the bond between mill scale and steel substrate. This is why mill scale hardens and cracks during the metal cooling process creating a corrosion cell. In order to insure the corrosion resistance of the powder coating, removing mill scale cracks may increase the time required to sandblast.
Sandblasting is not an effective method for removing grease, oil, or other lubricants. Even the slightest presence of caulking or gasketing can create finishing problems. When oil or grease is present it will contaminate the blast media, and can spread contamination over the entire work product. Contaminants lead to premature coating failure and an expensive media reclaim bill.At Aegis, we are equipped to degrease most parts, but products sent to us free of these contaminants require less time (cost) for sandblasting.
Where and how your part is going to be used dictates how clean the substrate needs to be after sandblasting. Aegis follows the cleanliness standards as defined by NACE and SSPC. If you do not have cleaning specifications for your project, we can provide you with guiding questions to determine how clean your product should be and accurately estimate the time required for sandblasting.
The accessibility of the surface to be sandblasted will have an impact on how we are able to prepare it for coating. We have equipment that allows us to blast the inside of pipes and other recessed - internal areas. Depending on the complexity of the job and the degree of cleanliness required, it is good to discuss other options in the fabrication and design that could reduce the complexity of the job.
Many of our customers rely on our expertise in cleaning and sandblasting. There are some industry standards, such as AWWA-C213 that have specific requirements when it comes to the type of media and blast cleanliness that is required. We can help you determine the necessary requirements to ensure a high quality finish.
Aegis sandblasting expertise is just a call away. You can also request a free quote on sandblasting.