Why Surface Prep is The Most Important Step in Coating Application

Why Surface Prep Matters

Surface preparation is the foundation of every successful coating application. No matter how advanced a coating is, it can only perform as well as the surface beneath it. Skipping or rushing surface preparation can lead to coating failures such as peeling, blistering, rust formation, and poor adhesion. If there is surface corrosion, old coatings, grease, or other contaminants left on the surface, they can prevent the coating from bonding correctly, decreasing both its performance and lifespan. In many cases, inadequate surface preparation can also impact the functionality of the finished part or the equipment it is used in.

For example, applying a coating over a rusted surface does not stop corrosion. It simply traps it beneath the coating. The rusted areas remain weaker than the surrounding material and can continue to spread over time. As corrosion progresses, the coating may begin to crack, blister, or separate from the surface, allowing moisture and other contaminants to penetrate the part. This accelerates corrosion and compromises the coating, which will ultimately lead to premature part failure.

What Does Proper Surface Preparation Look Like?

Proper surface preparation is much more than simply rinsing a part before coating. Many manufactured parts arrive with oil, grease, rust, or remnants of old paint and coatings that must be removed for the coating to bond properly. Depending on the part and the material, the process may include thermal prebake (to loosen contaminants), surface blasting to remove rust and old coatings, and an alkaline wash or degreasing step to leave the surface clean and ready for coating. Every part is different, but taking the time to thoroughly prep the surface helps ensure the coating performs the way it’s designed to.

Blistering                                                   Peeling                          Chipping

Could a Higher Bond Strength Coating Be Used to Combat Poor Surface Prep?

In short, no. Even the strongest adhesive coating can not make up for poor surface preparation. If the surface is not properly cleaned and prepared, there will still be weak points where the coating can not bond as intended. Something as small as a speck of dust, grease, or other contamination can interfere with adhesion, causing the coating to peel, crack, or fail over time.

DECC’s Surface Prep Process

At DECC, every project begins with evaluating the condition of the part before selecting the appropriate surface preparation. There are three main types of surface prep, and DECC has in-house cells for each process. The three types are mechanical, thermal, and chemical. Depending on the material and coating requirements, components may go through pre-bake, sand blast, alkaline wash, phosphate preparation, or other pretreatment steps before coating begins. Once coating is applied, parts are then tested and inspected to make sure the coated area meets all requirements.

At DECC, we offer a variety of in-house surface preparation methods to ensure every component is ready for coating. To learn more, check out our blog post on Common Surface Preparation Types. If you’re unsure which process is right for your application, contact our team to help determine the best one.