Pre-treatment

Metal Pre-treatment prior to power coating is an essential step to ensure proper coating performance. There are two steps to pre-treating the metal before applying the paint:

1. Mechanical Surface Preparation.
2. Chemical Surface Preparation.

For power coating, the most commonly used method is chemical pre-treatment.

The pre-treatment applicator must know the following:

• Need for pre-treatment
• Surface Preparation
• De-rusting processors
• Activation
• Conversion coatings; mild steel, galvanizing steel, aluminum and mazak
• Trouble shooting

Whats the need for pre-treatment?

Performance of powder coating on a metallic surface mainly depends on proper pre-treatment of the substrate.

Pre-treatment is an important factor for 3 reasons:

1. Provides a clear, uniform, oil-grease free surface.
2. Provides good adhesion of film.
3. Forms an inert layer which inhibits the corrosion of the paint film.

The pre-treatment processes we offer at One Stop Coatings are:

• De-greasing
• Water rinse
• De-rusting
• Activation

De-Greasing at One Stop Coatings:

Chemical de-greasing methods used in any particular application is closely related to the nature of the surface being cleaned and the amount and type of contamination.

The process we use for this type of method is solvent wipe. This is known to be the best method to remove heavy/sticky oil/grease from the metal surface and since all solvents are almost neutral, they do not attach to the base metal.

Shot Blasting at One Stop Coatings:

We offer an on-site Shot Blasting facility up to SA3 grade.

This process removes contaminants such as rust and old paint. This gives a good adhesive surface to start the powder coating process. Shot blasting new fabrications can offer a long lasting life to the powder coating.

We also offer a service for old metals to be re-furbished such as bike/car parts, garden funature, driveway gates etc. After the powder coating finish, this will give your items a fresh new look!

Galvanised steel at One Stop Coatings:

Despite the fact this preparation process has been avaliable for some time now, T -Wash is still generally considered to be the best pre-treatment method for galvanised steel prior to coating. T - Wash is a modified zinc phosphate solution which contains small amount of copper salts. When applied, a dark grey/black discolouration of the zinc surface will result.

After the pre-treatment process of galvanized steel, we apply a de-gassing powder coating finish to prevent pin-holing on the surface.

At One stop coatings, we also offer a range of primers to be applied before the final top coat. These are:

• Etch Primer
• Zinc rich epoxy primer

Etch primers are most suitable to aluminium, stainless steel and weathered galvanized steel. This process allows maximum surface adhesion for the next coat on the metal.

Zinc rich epoxy primer is recommended to all mild steel that is for external use. This process is applied to the metal, before being semi cured to allow the final coating to be applied. This process allows great adhesion on both self coloured mild steel and shot blasted mild steel, and provides anti corrosive properties which will keep rust away from the powder coated work for up to 16 years.