Powder Coating vs liquid paint

Powder coating offers the consumer a superior finish while adding many performance properties such as excellent resistance to corrosion, chemicals, heat, impact, abrasion, UV rays and to extreme weather conditions. Not only is powder coating exceptionally tough and impact resistant but it is more cost effective than most other coating options.It is usually a one coat system that is thicker and more durable than the older method of liquid painting which usually consists of several coats being applied.

One of the best reasons for using powder over a liquid paint finish is that it is environmentally friendly and virtually pollution free. No volatile organic compounds (VOCs) or solvents to evaporate into the atmosphere to create health risks for our employees, the general public, or to pollute the world we live in.

Powder is so environmentally friendly that all of the airborne powder in our spray booths goes through the powder filter system and can be vented back into the work area. In fact, one of the major elements in expanding the market for powder coating has been the implementation over the past 30 years of stringent air pollution controls set by environmental protection agencies.

Best of all, powder coating is a superior but cheaper alternative to liquid painting.

Zinc substrates

The main reason for the blistering, pinholes or craters is out gassing from within and under the zinc coating. There are several methods to minimize or eliminate these problems

  • Preheat the substrate to above the intended bake temperature to degas the zinc coating before powder coating.
  • Use slower gelling powders to extend out the ‘wet stage’ in the baking cycle of the powder, allowing more time for the gas bubbles to expel and the now molten powder to flow back out before the powder begins to set.
  • Add a degassing agent to the powder specified to slow down the gelling process (as above).

Poor adhesion of power coating to zinc substrates can be caused by the zinc galvanisers quenching the items in a strong chromate bath to cool the items down and to slow down the formation of a zinc oxide layer. This causes problems at the powdercoating stage as it is very difficult to remove this chromate coating to be able to etch and treat the zinc before powdercoating. Usually if it is explained to the galvanizer that the item is to be powdercoated, then they will usually air cool the items. But many informed zinc galvanisers now tend to use a very weak chromate quench bath which seems to be acceptable to the powdercoating industry.

Custom made Powder colours and textures

Almost anything is possible. Depending on your requirements, powder can be made from several different types of resins depending on whether it is for indoor use, UV requirements, chemical resistance, anti microbial, heat resistance, mar resistance or a combination of the fore mentioned. However, it is important to note that powder is made in batches, as opposed to paints which can be made by tinting a standard paint base (as small as 1 litre tin) to achieve your color and finish. Powder coating colours can be matched to almost anything. If the colour and finish required is not within the standard powders available, then the powder (with a texture, if needed), can be matched by sending us a colour swatch and description of the environment the powder will be subject to so as we can forward this onto the powder manufacturer. Extra time should be allowed for this process.

Custom powders are usually made in 50kg minimum batches which is the equivalent to 50 litres of paint at an approximate cost of $1,000 – $1,500.