The Powder Coating Process ...


At Metalwise we have many years experience in sandblasting, shotblasting and powder coating items to give a superb finish.

It is vital that items to be powder coated are thoroughly cleaned before beginning the coating process. In order to do this without pollution we use a machine which uses an aqueous system. This does away with need for dangerous chlorinated solvents that were traditionally used in open topped vapour degreasers - these were commonly known as trike tanks (short for trichloroethylene).

The Phoswash machine is ideally suited to metal fabrications which need pre-treatment prior to powder coating and is also commonly used for phosphating lengths of extruded bar. The machine is supplied with two rails inside which hold a standard perforated floor on which components can be placed. This floor can be simply lifted off the rails and an optional docking bogey can be used.

The machine also provides us with the capability to supply Phosphate coating to Defence Standard 03-11. The Vixen phoswash pre-treatment machine is a 3 stage phosphate process. This will give excellent paint adhesion, and prolong the life of the powder coating or the wet paint work.

The metal components are first washed in an iron phosphate solution and then rinsed automatically. The phosphating process increases corrosion resistance and greatly improves paint and powder coating adhesion.

The coating conforms to BS3189 Type 4 and DEF STAN 03-11 Class IV specifications.

The grade or size of steel shot will determine the ultimate finish achieved on the surface of the metal. The round ball shape of the steel shot produces a clean, smooth and polished surface through a peening action created by the acceleration of the shot. In a peening application, steel shot is also used to impart compressive strength to torque or load bearing metal parts such as crankshafts, engine turbine blades and heavy-duty springs. Steel shot blasting is the most widely used process for cleaning, stripping and improving a metal surface.

For wheels, all tyres, valves and weights are all removed then we delicately strip the wheel. The purpose of this is to remove as much paint as possible.

The wheel is then rinsed off with cold water. We then go to the blast room where we use a fine grade of grit to remove any final traces of paint and also to give a key for the powder coating. We now have a clean paint free wheel. The next stage is to remove any kerbing damage that the wheel has. If the wheel is badly curbed or cracked then we will repair the wheel but there may be a small charge. We can also remove any bad dents that the wheel may have suffered - however in some cases the wheel may be too badly damaged for us to repair in which case we will contact you before going any further.

The wheel is placed in the oven and brought up to full curing temperature which is 180 to 200 degrees. The purpose of this is to degas the wheel. A primer is applied plus a top coat of the required colour then the wheel is put back in the oven at the curing temperature to allow the powder to cure. A powder lacquer is then applied and the wheel once again is placed to cure. We check the wheel to make sure the quality is acceptable and that is it.

Tyres are then refitted and wheels balanced and where applicable wheels can be put back on the car. If you require we can also paint wheel centres to match. Powder coating is a dry finishing process, using finely ground particles of plastic powder which are electro-statically charged and sprayed onto a part to be coated. The parts to be coated are electro-statically grounded so that the charged powder particles projected at them adhere to the parts and are held there until they melt and are fused into a smooth coating in the curing oven. The result is a uniform, durable, high quality finish that is also environmentally friendly. It looks like paint but it acts like armour.

Powder coating is a highly durable, decorative and long lasting finish applied to products of nearly every sort for the consumer and industry alike. It can come in virtually any colour or finish, matt or smooth, is rust-free, scratch resistant and ecologically friendly.

The powder coating process uses a solvent free mix of plastic resins, pigments, and fillers that melt and fuse together when heated. The solid particles of coating are electrostatically charged in a spray gun and carried by low velocity air to the surface of the piece to be coated. The electrostatic charge holds the powder particles in place while the part is cured at around 200 deg C in an oven. The heat of the oven causes a chemical reaction to occur and the powder to cure, creating a highly durable finish. Wheels In all cases we fully refurbish the wheel, with the tyre off. You can bring your wheels to us without tyres, or we can strip and refit the tyres and re-balance the wheels for an additional charge. (The weights are fitted to the inside of the rim so as not to spoil the appearance of the wheel).

Finally a clear lacquer coat is applied over the first coating in the same manner, thus enhancing and protecting the alloy wheel. Many finishes and colours are available on request.

Epoxy Powder Coatings: Ideal for internal aggressive applications, combining excellent mechanical properties with a high degree of chemical resistance. Developed to comply with the most demanding corporate and legislative specifications.

Epoxy Polyester Powder Coatings: A blend of epoxy and polyester resins, which offer both designer and coater the optimum combination of decorative and protective properties on a wide range of internal components. It combines speed of use, good overstoving stability with excellent colour and gloss retention.

Polyester Powder Coatings: These coatings are tough and attractive, providing excellent weathering characteristics on external surfaces. TGIC Free formulations are available within our range.

Polyurethane Powder Coating: These coatings provide exceptional levels of gloss coupled with clean sharp colour. They combine good chemical and mechanical properties for interior and exterior applications where a high degree of performance and appearance is important. This product exhibits good heat resistant properties, as well as good flow and being resistant to weathering. Gloss and flow are superior in appearance to most other powder coatings. Powder Coating can be used on a variety of materials and is available in a wide range of colours, gloss levels and other types of finish.

Types of Finish Available: Smooth Antique Leatherett Texture Metallic Anti-Bacterial TGIC Free MOD Colours and gloss levels available on request.

Please contact us so we can discuss your exact requirements.