When it comes to surface finishing of a metal product, many people are undecided between powder coating vs paint. Which is best? We take a look at the pros and cons to help you decide on what’s best for your particular project.
Both powder coating and wet paint contain additives, resins, and pigments. The main difference between them is solvent, or lack of it, in the case of powder coating.
The solvent in wet pain works to keep all the other ingredients in a suspended liquid form. This is in complete contrast to powder paint which is applied in the form of dry powder. All of the other differences of powder coating vs paint, namely
- Application method
- Colour matching
- Operator training requirements
originate from the basic difference in the chemical composition.
Powder coating vs paint – Application method
Surprisingly, despite them being applied in two different formats, liquid vs solid, the industrial methods of applying wet paint and powder coating are quite similar.
Both processes require the same pre-treatment – thorough cleaning of the surface. Any dirt, oil or moisture will interfere with adhesion to the surface.
For powder coating
In this instance, dry powder is delivered through an electrostatic gun on to the metal exterior. The gun negatively charges the powder which attracts it to the grounded part. This attraction results in even, fast application.
Once the coating is sufficiently thick, the coated item is placed in a curing oven which causes the heating powder to gel. The process of curing creates a thermal bond between powder particles that results in a smooth hard finish.
For wet paint
A fine spray is used to disperse liquid paint. While it is also electrostatically charged, it’s to a much lesser degree. Liquid paint needs to be applied by trained experts to avoid sags or drips whereas powder paint forms an even coating with relative ease.
Some liquid paints are placed into a curing oven whereas others are air-dried.
It’s usual for both liquid paint and powder paint to include a primer coat in addition to a colour coat. However, liquid paint may include multiple coats as well as a clear topcoat.
Some textures can be achieved equally well by powder coating or liquid paint whereas others are easier to achieve with a particular type of coating.
For instance, it’s easier to achieve textured finishes with powder coating. Thinner coatings are naturally more textured whereas more layers achieve a smoother finish.
While a high gloss finish can be achieved with powder paint it’s far easier using liquid paint.
Powder coating vs paint – colour matching
Liquid paint is the outright winner when it comes to colour matching. Liquid paint colours can be custom mixed easily on-site by almost any paint supplier. For example, blue and red mixed together will create purple.
On the contrary, custom powder coatings require a special production run since the colour is determined by the plastics that have been ground down to form it. As there is no solvent in powder coating, blending red and blue powder would simply achieve a speckled red and blue pattern.
Power coating outperforms wet paint since it is more resistant to scratching, chipping, and other wear and tear. This is because it can be applied in several layers and because of the thermal bonding it goes through during the curing process. This makes it particularly useful for outdoor products such as bollards and bicycles.
Power coating also retains its colour better than liquid paint.
Health and Safety
Not only is powder coating more durable than wet paint but it’s also safer to store and apply.
Wet paint is hazardous because it’s flammable. It’s also hazardous to the people that apply it because it emits volatile organic compounds that can cause respiratory problems.
Finally, powder coating is cheaper than liquid paint although the initial up-front costs may be higher.
Hopefully, this has given you a better insight into the powder coating vs paint debate. While there will always be a place for liquid paint, you can expect to powder coating used more regularly.