A COMPREHENSIVE LOOK AT SURFACE PREPARATION METHODS

COMMON METHODS FOR COATING REMOVAL, SURFACE CLEANING AND ADHESION PROMOTION

In order to prepare a surface for high strength structural bonds or for non-destructive inspection and evaluation, it is important to thoroughly remove all coatings and contaminants on the sample surface. These include coatings like paint, varnish, oil, grease, wax and decals, as well as things like dirt, grime, machining fluid, rust, general corrosion, and residue from previous penetrant inspections.

Proper preparation of the sample surface is crucial to achieving accurate results when testing, particularly when critical assets are involved. Surface preparation typically encompasses three things – coating removal, surface cleaning, and adhesion promotion. Here, we will go through various methods of surface preparation for each of these use cases along with their pros and cons, and explain how plasma is the only method that handles all three primary use cases in an efficient and effective manner.

plasmablast coating removal

coating removal

When it comes to coating removal, most common industrial techniques for surface preparation involve the use of either chemical agents, abrasives, or both in conjunction. Depending on the specific coating or sealant that needs to be removed, as well as the nature of the substrate material, the specific methods used for coating removal can vary wildly. This is because the use of chemical cleaning and abrasive methods needs to be tailored specifically to the coating and the substrate to ensure effective coating removal with as little damage to the underlying material as possible.

Chemical methods for coating removal, when executed correctly, can be designed in a way that is tailored to a specific coating and substrate combination. This would ideally result in effective coating removal with less risk of substrate damage. However, there are many drawbacks to chemical coating removal. Not only are the chemicals used for coating removal harsh for both the operator and environment, but the chemical coating removal process creates harmful byproducts that must be remediated and disposed of properly. This greatly increases labor costs and the costs associated with disposing of corrosive chemicals.

Abrasive methods for coating removal are also commonly used, but these too have significant drawbacks in many cases. While abrasive methods can be “simpler” and do not involve chemicals (though sometimes they are used in conjunction with chemical methods), these methods are a lot more labor-intensive. Especially if the target surface requires very fine, thorough removal of coatings, the labor costs involved can be very high.

In addition, abrasive methods carry a much higher risk of accidental damage to the substrate material, especially if there are power tools involved. This can be a huge drawback especially if the assets being worked on are critical in nature. Also, despite the lack of chemical byproducts that need to be cleaned up, there is still the risk of inhalation of fine particulate matter given off during abrasion. This can pose a risk to the health of the operator, especially if the work environment is small and indoors.

Coating removal methods involving atmospheric plasma, in contrast, eliminate virtually all of the drawbacks associated with both chemical and abrasive methods. Atmospheric plasma can be used to remove a wide variety of coatings ranging from paints to sealants, epoxies, powder coats, silicone and other organic coatings with ease. In addition, plasma can be used on a variety of materials with zero substrate damage. Coating removal using atmospheric plasma also involves a lot less labor and cleanup (at up to a 90% savings!) and carries a minimal, marginal risk to the operator and the environment.

PB 7000-M Advanced Surface Preparation

SURFACE CLEANING

Most industrial surface cleaning operations are done to remove dirt, grease, oil, rust and corrosion, adhesives and other chemical residue from the substrate material. Traditional cleaning processes can be complicated and involve several steps for surface preparation. Often, a combination of different methods is used to clean a surface. These include chemical cleaning for degreasing and coating removal, steam cleaning, and the usage of hand or power tools, but the exact methods and their intensity can vary depending on the substrate and the level of cleaning required.

Not only do these multi-step processes require a lot in the way of labor, setup, tools, and consumables (chemicals, cleaning agents, etc.), but there is a lot of work involved after the cleaning is complete to remediate and dispose of the byproducts.

Here again, the advantages of using atmospheric plasma become apparent. Our PlasmaBlast®  tool, for example, is effectively an all-in-one cleaning tool that can be used to eliminate several steps from the traditional surface cleaning process. While the surface might still need to be degreased and freed of dirt, the chemical and abrasive cleaning steps can essentially both be replaced with atmospheric plasma!

ADHESION PROMOTION

One of the main reasons that coating removal and surface cleaning are performed in industrial contexts is to prepare the target surface for adhesion. In order to form high strength structural bonds between two surfaces, it is important to remove any and all surface contaminants, and to either etch or improve the surface’s receptivity to adhesives in some way.

The first step of improving adhesion is typically to perform a cursory surface cleaning to remove grease, dust, and dirt that may be on the surface. After this is when abrasive and chemical methods are typically involved to remove rust, corrosion, and any coatings or residue that might otherwise be present on the target area. These chemical and abrasive methods are also often employed to help etch the surface to make it more receptive to adhesive bonds.

As with surface cleaning, the use of abrasive and chemical methods can lead to increased complexity, material and labor costs, and other costs associated with cleanup and waste disposal. However, the use of plasma, particularly atmospheric plasma, can consolidate and streamline adhesion promotion processes significantly.

Plasma can eliminate the need for the use of abrasives and chemicals to clean and etch surfaces by getting rid of any corrosion or chemical residue on the surface. Plasma has also been shown to increase surface receptiveness to adhesives and other treatments and bonds, without the other drawbacks involved with chemical and abrasive methods.

CONCLUSION

In conclusion, while there are many different methods and workflows for surface preparation in an industrial context, whether for coating removal, surface cleaning, or adhesion promotion, each of these methods carries its own set of drawbacks. However, in our opinion, atmospheric plasma is, on balance, the most effective and efficient tool to use in surface preparation workflows.

Our PlasmaBlast®  tool is lightweight, ergonomic, portable, media and chemical free, and is built to withstand use in even the harshest conditions while providing up to a 90% labor savings! PlasmaBlast has also been validated and tested and proven in the field by Fortune 100 companies, the US Navy, US Air Force and NATO.

To learn more about our PlasmaBlast®  system and how it can streamline your surface preparation workflows, give us a call at (919) 341-8325 or fill out the contact form and one of our representatives will get in touch with you to coordinate a demo, sample evaluation or quote!

plasmablast pb-7000m tool
PLASMABLAST® PB 7000-M