Properties of EDP Coating

Process Description: "EDP" (otherwise commonly known as E-COAT, or ELECTRO-PAINT) is more technically termed -- CATHODIC ELECTROPHORETICALLY DEPOSITED PAINT.

The paint formulation applied is the latest Lead Free type "Medium Build" Epoxy.

The process, which is fully automated, PLC controlled, utilises 10 preparatory immersion steps including cleaning, and fine grain Zinc Phosphating before the Painting stage. Post painting, the coating is oven cured at 175 C.

The coating is eminently suited for application over wrought and cast steels/irons, zinc or aluminium diecast, bronze welded, and zinc coated steels. Unlike other electroplated coatings, the EDP process is capable of coating into deep recesses in complex shapes while maintaining a uniform thickness. It is the coating that has enabled the automobile and outboard motor manufacturers of the world to provide six-year corrosion warranties under severe salted roads and salt-water environments.

Coating Properties:

• Hardness: Minimum Scratch hardness- 4H pencil equivalent; high level of abrasion resistance in general usage.
• Colour & Gloss: Black, semi gloss maintained to approved standard limits.
• Paint Film Build: 15 or 20-micron minimum up to 35 micron maximum (controllable).
• Corrosion Resistance: Per 5% Neutral Salt Spray Test to AS2331.3.1- 2001 (ASTM B117) – for 20μm coat, 840hrs + to onset of red rusting or < 3mm corrosion undercut or loss of adhesion from the edge of pre-scribed X lines . Applied over zinc plated steel, the corrosion resistance increases from 840 hrs, to up to 2000 hrs depending on Zinc thickness.
• Adhesion: As described by the above Corrosion Testing, and also by a standard peel off adhesive tape test where no square or part thereof of the paint coating shall be removed from a 10X10, 1mm scribed line grid. In practical service, the coating will not chip or peel away from a scratch.
• Warm Water Immersion Resistance: Nil degradation after 1000hrs at 50 C.
• Temperature Resistance: Nil degradation or loss of adhesion in air at temperatures of up to 140 C., either constant or cycling to room temperature.
• Chemical Resistance: Resistant to mineral and vegetable oils, hydraulic fluids, glycols, gasolines, weak acids, and common organic solvents.. Not resistant to warm caustic.
• Ultra Violet Radiation: Poor resistance to prolonged exposure - will degrade by slow colour fade and chalking. Where prolonged exposure is expected, this may be readily overcome by the application of a simple acrylic, enamel or powder topcoat.
• Lead Free: All 3 Wilcox lines utilise the latest generation Lead Free paint formulation.
• Conformance to Automotive Company Requirements: Meets a large range of Automotive Specifications for applications requiring under body corrosion resistance to severe environments, resistance to corrosion initiation by stone chipping (Gravelometer tests), etc.: - eg. GM HN1636.

Notes on part design

The design of parts should take metal finishing processes into consideration. Lack of suitable drainage will cause pooling defects. Lack of air release will cause air pockets where protective coating is not applied. Blind holes will cause staining and build-up of paint around the hole. Very small diameter holes can randomly block with paint. Threaded parts need to allow for paint thickness. Suitable racking holes will minimise contact marks.