Duality has existed since the beginning of everything, interweaved in the very fabric of nature. Some of this duality receives a lot of public attention while the rest is subtle, emerging only as it becomes more important in certain situations. The sheet metal fabrication business, for instance, witnesses grudge matches between the most ideal finishing techniques for individual products, and the decision is rarely unanimous, if ever. When putting wet paint and plating versus powder coatings, you will find yourself assessing each case individually to reach a decision. In order to choose the best sheet metal finishing technique for your product, you must first understand where each of them succeeds and fails, as well as the basic principles and processes involved. This is what we have attempted to outline in this article.
The finishing process involves the electrostatic application of a dry powder, a free floating coating on a surface which then settles into place with the application of heat. This powder coatings comes in a number of varieties depending on whether it is made of polyurethane, polyester, acrylics, straight epoxy, or polyester epoxy. The outcome of the powder coating finishing process is a tough, thick finish, which is harder and more durable than common paints. This kind of coating is popularly used on a number of products, including automobile parts and various household appliances.
When powder coatings a surface, one of these two processes can be opted for: thermosets and thermoplastics. Thermosetting makes use of chemicals that react to the powder when heated, whereas thermoplastics melt and set into the coating upon heating, and no additional chemicals that react to the powder when heated, whereas thermoplastics melt and set into the coating upon heating, and no additional chemicals are involved in the process. Barring this, the two processes are almost similar and appear visually identical. The thermoplastic and thermoset powders are created by binding the powder input, applying heat to the mixture, and rolling out the polymer product, which is then broken down into chi[s and ground further until a fine powdery state is achieved.
When the powder has been created and is ready to be applied, the surface is readied for application. This normally involves wiping the metal surface clean of any oils or debris that may prevent the powder from attaching completely. Next comes the electrostatic application, where a high voltage electrostatic surge charges the dry powder and the surface. Charging up the powder and the surface in this manner enhances the efficiency of the coating by as much as 95%, reducing paint wastage and ensuring the product is completely coated. The coated object is then left under a high temperature of 400 degrees for 10 minutes to allow the coating to set onto the surface. The high temperature melts the powder, allowing it to wrap around the object, all the while binding the polymer into a heavier network like polymer finish.
Advantages of Powder Coating
Powder coating has a number of benefits, one of which already has been mentioned earlier. Powder coating a metal object allows for a dense sturdy finish, more durable than conventional paints. Secondly, this process only requires a single coat so it is fast, efficient, and easy. In addition to its ease of application, it allows for custom textured and coloured finishes as the powder involved can be nicely manipulated. Furthermore, powder coating objects result in a remarkably even finish as the powder melts and sets across the entir eobject at once, leaving no application traces or drips. Finally, the powder coating process is environmentally friendly as it produces minimal volatile organic compounds.
Disadvantages of Powder Coating
With a number of benefits, there are also some disadvantages of powder coating. The first is its inability to produce a thin finish. Although a thick finish on metal objects works well in most cases but some objects require a thinner finish which is where powder coating fails. Attempting to thin the polymer results in a course. bumpy finish much like an orange peel. Another drawback is the complexity and expensive nature of the procedure, making it unsuitable for small scale sheet metal applications. The process requires electrostatic equipment, spray materials, and an oven which could all be too much work and expense for a minor application.
Wet paint has been used for years as the conventional finishing coat, although the process has seen various changes with technological development. A majority of sheet metal fabrication procedures make use of a pump, spray, or another form of a pressurised applicant to evenly deliver the paint over the metal surface. Plating, on the other hand, is the process of depositing metal on a conductive metal surface – think gold plated jewelry. Objects can be plated for the purposes of decoration, hardening, corrosion prevention, friction reduction or to improve paint adhesion and wearability.
Similar to powder coating, the metal surface is wiped thoroughly clean first, after which liquid paint is evenly onto the object to a thickness of about 15-20 micrometers. The process ends once the object has been evenly coated with paint to the required thickness. The plating process is much more complicated and will vary depending on the metal being used for plating and the required finishing effect. The general procedure involves the object being covered with the plating metal with heat and pressure being applied to the metal and the object to fuse them together. Some processes will also use certain liquids, vacuums, or vapors as substitutes to heat and pressure.
Advantages of Painting
Wet paint and plating excel where powder coating fails. Its first benefit is that it can be used to coat objects that cannot be heated, as the process does not require high temperatures to succeed. The second benefit is the wide range of colours paint finish and plating can produce, allowing for much more custom colour woks than powder coating. The third advantage it has over powder coatings is its ability to produce a thin finish, making it ideal for objects that require one. The final benefit is economic; wet paint is more affordable as a finishing process than powder coating, making it suitable for both large and small finishing applications.
Disadvantages of Painting
The disadvantages of both wet paint and plating is their lack of durability as compared to powder coatings, with both requiring regular maintenance and refinishing from time to time. The second disadvantage of paint is its inabilty to achieve an even finish the first time around, with the object requiring several coats to attain an unblemished and even finish. Unlike powder coating which uses powder as the initial coat, this process uses liquid paint which can be tricky to spread across the body of the object keeping the thickness consistent.
So, if you are interested in our painting service please make sure to get in touch with CJ Coatings today at 0808 189 2362.