The importance of pre-treatment prior to powder coating Toronto
Pre-treatment of a surface prior to powder coating Toronto includes removal of dirt, oil, grease, metal oxides or welding oxides to enhance adhesion. Pre-treatment can be done through chemical or mechanical methods but the choice will depend on the size and type of material including the kinds of impurities that have to be removed.
Solvent cleaning is the cheapest and best method that removes heavy and sticky oil and grease-like substances from any surface. Solvents are almost neutral and they do not attach to base metal. Solvent is applied through a rag or cotton that has been soaked in a suitable solvent like kerosene or benzene.
Phosphating is another pre-treatment method that consists of the deposition of the metal surface of insoluble metal phosphates that are chemically bonded to the substrate. Phosphating provides a clean greaseless surface and a corrosion inhibitive base for powder coating Toronto.
Oxide and scale removal can be effectively achieved through mechanical scuffing, wire brushing or abrasive blasting for large areas. Coarse expendable types of abrasives have taken over the traditional use of sand and it is now augmented by a wide range of ultra-fine abrasives to achieve surface uniformity.
Drying and curing processes in powder coating Toronto
Drying and curing are energy intensive processes because they are usually done through convection ovens. Convection ovens when used with large parts can be rather costly since evaporation and curing are dependent on the bulk temperature of the part. In order for the part to dry and the powder coat to cure, the whole part must be hot enough. Large volumes of air are required to be heated and exhausted from the convection oven so that the parts will be effectively dried and cured. This issue is not present for thin walled and low mass parts since hot air can heat the parts quickly for a faster drying and curing process.
Infrared curing can be used on parts with small geometries. Heating goes where it is needed on the surface since there is instant infrared light absorption. Rapid part surface heating will result into better powder flow with less chance of dirt defects since there is relatively little air flow to deposit particles compared to convection heating. Infrared light only heats the part surface and not the paint and therefore results in paint drying from the inside out. The paint will not skin over or trap solvent or water inside the paint that usually happens when convection oven is used.