Most powder coatings have a particle size in the range of 2 to 50 μ (Microns), a softening temperature Tag around 80 °C, a melting temperature around 150 °C, and are cured at around 200 °C. for minimum 10 minutes to 15 minutes (exact temperatures and times may depend on the thickness of the item being coated). For such powder coatings, film build-ups of greater than 50 μ (Microns) may be required to obtain an acceptably smooth film. The surface texture which is considered desirable or acceptable depends on the end product. Many manufacturers prefer to have a certain degree of orange peel since it helps to hide metal defects that have occurred during manufacture, and the resulting coating is less prone to showing fingerprints.
There are very specialized operations where powder coatings of less than 30 micrometers or with a Tag below 40 °C are used in order to produce smooth thin films. One variation of the dry powder coating process, the Powder Slurry process, combines the advantages of powder coatings and liquid coatings by dispersing very fine powders of 1–5 micrometer-sized particles into water, which then allows very smooth, low film thickness coatings to be produced.
Advantages over other coating processes:
- Powder coatings contain no solventsand release little or no amount of volatile organic compounds (VOC) into the atmosphere. Thus, there is no need for finishers to buy costly pollution control equipment.
- Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
- Powder coated items generally have fewer appearance differences than liquid coated items between horizontally coated surfaces and vertically coated surfaces.
- A wide range of specialty effects are easily accomplished using powder coatings that would be impossible to achieve with other coating processes.
- Curing time is significantly faster with powder coating than with liquid coating.