The Benefits and Drawbacks of Powder Coating
Powder coating is a process in which a powder is sprayed, in a sealed spray booth, over a typically metal product or item. The product is then heated to a specific overall temperature of the item for the powder to melt which creates a solid, even, thicker coating of a protective film. There are also liquid coating options, so why would anyone choose the powder version over the more traditional liquid coatings?
Well, we here at C Tek choose to powder coat certain products for a variety of reasons. They are more durable coating materials. Powder coatings can produce thicker and specialty coatings of color, texture, and finish options. It also less of a serious environmental impact on the area surrounding the workshop using the material to coat their products. The curing and drying process goes smoother than with the liquid coating options. Finally, the percentage of material that gets utilized is higher than other coating methods
Advantages of Powder Coatings
Durability
The durability of powder coating is superior to most other types of coatings. Once cured and hardened, the powder coating is extremely tough and can protect against abrasion, chipping, impact, chemicals, and weather. It is the perfect choice for anything marine-based as well because it can withstand up to hundreds of hours of direct salt spray without showing any signs of wear or even fading in their brilliantly vibrant color options.
Specialty Coatings
Because of the way that powder coatings are produced, they can make a much wider range of specialty coatings and finishes. They can be completely smooth or pitted to varying degrees and even textured to increase traction or grip. Also, they come in a vast array of super vibrant color options that do not fade even under severe situational exposers to many different things that would otherwise destroy a liquid coating.
Impact on the Environment
When it comes to performing the coatings, liquid coatings include a variety of VOCs or Volatile Organic Compounds that are highly regulated materials especially for workplaces that use them often or even daily. They have to pay for permits that only allow them to release so many VOCs from their shop in a given period of time with hefty fines for those who go over on the release of these compounds.
Other environmental impacts include no need for primer or hazardous waste disposal. The primer is interesting as well since many items that get powder coatings are aluminum which would otherwise require a highly toxic chrome primer before a typical liquid coating could be applied and hold correctly. The chrome is carcinogenic and just all-around bad news for those employees tasked with using and applying the aluminum primer material. As far as hazardous waste, when it comes to liquid coatings you have all the masking materials and overspray covered items that need to be disposed of properly because of the number of solvents required to apply the liquid coatings to the product. It is a large amount and is full of VOCs which, again, are very bad for the environment in many different ways.
Smoother Functioning Curing and Drying Processes
The curing and drying process of powder coatings requires much fewer materials to produce the proper conditions. To cure powder coatings, all you need is some even heat throughout the product itself or an oven in the case of liquid suspended powder coating applications. These are when you have the powder seeped in a liquid suspension and dip the product into the mixture and then heat cure for about 10 minutes, or more depending on product size and thickness of the material. Also, for a powder application, you only need a light air exchange that can even be processed inside of a workshop. While liquid coatings require you to have a well-ventilated spray area and another well-ventilated booth with filters on the air exchanges to absorb all those nasty VOCs, fumes from all the solvents, and other harmful byproducts. They also need to be cooked in an oven that has a high air exchange rate which requires much more power, man-hours during extended dry times, and also other cost draining equipment. Plus, it needs to vent outside in a non-frequented area to limit employee exposure to the harmful chemicals released during the drying and curing process of liquid coatings.
Also, because of all the added ventilation products needed for curing liquid coatings the amount of ventilation and other materials plus the extended drying times necessary means that each drying period costs more and takes longer to produce equivalent products. You have to regularly replace filters on the ventilation system because they become clogged with solvent fumes and VOCs. All these hidden costs make powder coatings much more attractive as an option for most applications.
Material Utilization
The amount of liquid material that gets wasted in the application process is excessive. You have overspray and the fact that it has to be cut with solvents to put apply it in the proper form for the maximum coating features. With liquid coating you produce a lot of oversprays, you cover masking materials with the coating material, and lose some to hose lines and other transporting equipment. With powder coating, you are using a pneumatic sprayer to drift a layer of powder onto the heated product so it melts on contact and can even be used with an electrostatic application. This is where electrically charged ions of powder coating material are sprayed over an opposingly charged metal product so that the two are electrically attracted to each other and very little material does not end up on the product. Plus, the little bit of material that doesn’t end up on the product can be meticulously cleaned up and reused again with the same coating batch. This means that nearly 100% of powder coating material is utilized in the application procedure.
Drawbacks to Powder Coatings
Liquid coatings require a lot of extra equipment that is not necessary and also takes more material to produce equivalent products. There are many drawbacks to using a liquid over powder coating product, but what are the drawbacks to using powder or liquid? That’s right, there are a few areas where liquid coatings are the better option to coat a product, and here are the main drawbacks to powder coatings and how it can be inferior to liquid applications in some situations:
Suitable Product Materials
Since powder coatings require the product to be evenly heated for the coating material to properly melt and become one continuous material, the substrate materials of products are somewhat limited. Typically, smaller metal products are the best candidates for application processes, you can also apply it to some plastics, medium density fiberboard, fiberglass, and a few others as well. As long as it will not melt, warp, or burn when added to the curing oven’s excessive heat for a short period, then it will be okay to use powder coatings. For all other substrates, a liquid coating is needed to properly protect it from the elements and actions around it when in use.
Thinner Coating Thicknesses Difficult to Produce
Powder coatings, when applied, tend to be of larger thicknesses due to the lack of control on how much material lands on the product with each pass over with the sprayer. With a liquid coating application, you can spray it in much thinner thicknesses and still evenly coat it, you just use a finer spray and fewer pass overs with the spray gun. Liquids can be applied in thicknesses of less than 6 mm, which is nearly impossible with the two ways in which powder is applied. With a sprayed powder, it comes out in varying densities and melts instantly to the products surface creating an even coating only as the powder turns liquid and slowly levels out the thin areas with some of the thicker ones. With a liquid suspended powder application in which you dip the product is powder in a liquid suspension, you cannot control the amount that sticks or pools up in lower areas on the surface. You are just more hard-pressed to produce an even, thin, and smooth surface coating using powder over liquid coatings.
Custom and Multicolored Finishes Take Extra Time and Energy
With the way you need to clean up the spray booth meticulously to resupply the powder to limit waste but also to change between color applications because you do not want two different powder materials for the coatings to mix or it is essentially rendered useless. If you collect every grain when you are done or ready to switch up finishes, colors, or any other powdered coating, then you save yourself by recycling the material and not wasting any. This takes man-hours. So, if you needed to create a product with multiple colors you will need to clean the booth out between each color or finish and then apply the next one once the first is done curing. The amount of human hours involved in the process begins to build up and become not so cost-effective as liquid coatings in some situations. The liquid is quick and easy to change over and requires little to no remasking or cleanup between coatings.
Large and Thick Parts Are Harder to Coat
When it comes to anything large or thick, it is harder to apply powders because you need bigger oven space for curing and drying and/or need to heat the item evenly hot enough for the powder application process. Plus, for liquid suspension applications, the dipping pool needs to be large enough to evenly dip and remove the product evenly for an even coating to occur. So, either way, it is not easy to use powder. If the item being coated is larger than your typical curing oven and also too big to be evenly dipped, then you will need to use a liquid coating in most situations.
Cost of Powder Coating
Both the liquid and powder coatings require a spray gun and spray booth of some sort. So, they are evenly priced up to that point. Even the material itself is evenly priced, although you do need to purchase solvents for the application process of liquid, it doesn’t add up to the initial startup costs of powder coating operations. This is mostly because a curing oven is more expensive than a high air exchange ventilation system. The ovens also take more electricity to power to the proper heats to transfer their heat fully to the typical metal products, so they heat up to the desired temperature. These start-up building costs for the overall operation often limit operations needing to produce coated items to use liquid setups, since they are much cheaper to begin using and therefore you recoup your investment quicker.
The Pluses and Minuses of Powder Coatings
As you now know, it costs more to start powder coating than a liquid coating, but in the much longer run it can even out or even become cheaper due to the smaller amounts of material losses incurred in the process. There are many situations where both could be used equally as well, but there are also many situations where the powder is preferred because it is a bit stronger, brighter, will hold color and finish longer, and is easy to apply. In other situations, liquid coatings are best used due to a large area needed application and it will not fit in a curing oven, or it needs a thinner coating due to a tolerance fitting or other reason and the powder cannot coat that thinly.
There are many reasons to use either one, but we at C Tek offer the means and opportunity plus if your product is of the right variety, then powder coatings are the superior coating material when applied perfectly which also takes some experience and expertise that is only learned through trial and error, unfortunately. Luckily our technicians have earned their stripes, so to speak, and are professionals at applying this material or setting up application operations for businesses. So, if you get the opportunity then try the powder coating, it may make a product more marketable for a whole host of reasons and expand its possible usage areas which also widens a product’s market. All these reasons are great positives to the powder coating concept and increase the reasons you should come see us at C Tek Solutions and let us go over your individual needs to produce a proper coating plan. Then, we can set that plan up for you to begin your own coating operations or use ours.