The Technology

To enable powder or paint to form a secure bond to a metal surface requires that the surface is not only clean but is also roughened or abraided. This type of uneven surface is called amorphous and if observed under magnification appears to have irregular peaks and troughs. It is this irregular surface that allows the paint and powder to form a 'key' giving a far superior adhesion than could otherwise be achieved.

Simply cleaning with solvents will not result in an amorphous surface, this can only be achieved by mechanic means, for example shot blasting or hand abraiding or alternatively by using a chemical process.

Chemical pre-treatment has traditionally used a series of immersion tanks followed by drying the parts in a large oven. This process requires a large floor space, uses large amounts of chemicals and is labour intensive. It was to overcome these failings that led us to produce our first Auto-Wash machine in 2001. Since then we have exported machines to many different countries and the Auto-Wash Machine has become a vital and integral part of many powder coater's production processes.

Steel Pretreatment

Mild steel along with most galvanised and zinc coated products can be processed with a combined detergent/phosphate solution followed by cold water rinse and drying.

This requires a standard two tank machine with a cycle time of twenty minutes.

Aluminium Pretreatment

Aluminium is far more resilient to chemical abraiding, the acidic content has to be carefully monitored and the spray duration increased from four to eight minutes . The resulting adhesion qualities are suitable for an interior grade finish and the Auto-Wash Machine is widely used for this purpose. However to achieve exterior grade finishing an Auto-Wash 4 tank machine is required, this uses a much stronger acid with a pH of 1.5. Multiple rinsing is also required. The cycle time is increased from 20 minutes to 30 minutes.