Metallic or Powder Coating systems allow you to cover surfaces with a hard-wearing finish that can be very pleasing to the eyes, but do you know what is involved in getting it to the finished product? First of all, let’s go over what metallic and powder coatings are, and then we will explore the steps that need to be taken to apply both.
Metallic coatings are made up of a metallic components or alloys. The coating structures a shielding layer that deflects extreme environmental situations, such as corrosion, oxidation and sunlight. There are four fundamental ways to apply the metallic coating, which include; thermal spraying, electroplating, hot dip galvanizing and sherardizing.
Powder coatings are put on as a dry powder substance. This is atypical to any other type of paint or coating. It is necessary to use a thinner for the filler and binder portions for it to be able to form into an appending liquid. The powder is made from either thermoplastic or thermoset polymer. Some of the advantages of using powder coatings is it’s durability against everyday use and it’s resistance to fading. There are numerous choices for tint and texture when using powder coatings.
The first things that needs to be chosen is the type of coatings and color that you will need for your job. The cure cycle, oven type, and fuel type will also play a part in the selection. As well as film width, intercoat bond, overbake endurance, powder particle size and the substrate.
The different powder types are functional coatings (when the coating needs to be able to do the job that it is put on for, such as on structures) and decorative coatings(this is used when the look needs to be appealing for things such as furniture and motor body parts).
Once your choice of powder coating has been made, the formulation begins. The unprocessed materials are then weighed and mixed and ready for the next step in the process. The mixture is put through: the extruder, chilled rollers, a cooling belt and into the chipper. After it has gone through the chipper, the process is completed by grinding it into the required particle size needed for your job.
The powder form, once it has been created, needs to be within a relatively cool and dry storage area free of contaminating airbornes. If the powder gets too damp or too warm it can damage the batch. As you can see already, the process to get it to the point of application is very intensive, so care must be taken when applying it to your material.
Application and Conditions
- Preparation - When preparing your material for the coating process, care must be taken to make sure that it is cleaned correctly, by pretreating it in a blast room. The type of material will determine the kind of blast media that will need to be used. There are also wash stations that are used when dealing with any chemical, oil or solvents. An additional drying step might be needed if the wash station was used.
- Application - A Powder gun that is electrostatically charged is used within a spray booth, so it is in a controlled (for temperature and containment purposes) environment. When the application takes place in an enclosed or partially-enclosed area, any unused powder can be able to be gathered up and reused via a reclamation system. The use of the enclosed structure is imperative for keeping any airborne contaminants from getting into your powder mixture, as this can alter the results.
- Curing Ovens – The final phase in the powder coating process is the curing process. The item or items will be placed into a 325 to 450 degree heated enclosure that is designed as a curing oven. The time that it takes to cure will depend on the material being covered and the size of the item.
The journey that powder coatings take from start to finish is quite remarkable, and one has to have patience if you want the job done right. If you are thinking about using metallic or powder coatings yourself, you will need to make sure that you have the right equipment and take the correct measures for the best outcome. If you are not up for the challenge, many great companies can do the work for you and have the required equipment for any size job.