Iron Phosphate Pressure Wash Conversion Coating
HP phosphate is a cleaner/conversion coating product used in a high-pressure wand spray washer. It deposits an iron phosphate coating which improves paint adhesion and corrosion protection of steel, aluminum, and galvanized surfaces. It cleans and conversion coats at the same time.
Using HP Phosphate in a pressure washer allows you to prepare large fabricated items for painting in one pass. No long dwell times or second passes are required.
It can remove light rust and often eliminates the need for sand or media blasting.
The product has two accelerators. A room temperature accelerator that deposits a light but high quality phosphate coating. The other deposits a heavier iron phosphate coating at high temperature. Normally, this product is used at higher temperatures because it provides better cleaning and greater paint adhesion.
Use
HP Phosphate operates at a very low concentration. Best results are obtained using it at 0.75 to 1.00% by volume. Typically, it is used at slightly less than 1%. Higher concentrations should be avoided because they can cause flash rusting problems.
A rinse is not required, a rinse will usually provide better corrosion protection to painted parts.
Although it can be used at room temperature, better cleaning and a higher more corrosion resistant coating is obtained using the product at 160-180 degrees Fahrenheit. Very short contact times are needed at higher temperatures to deposit coatings, just a single pass over. At room temperature a longer contact time is required.
The parts can be air-dried but drying can be accelerated by using an air blow-off or an oven. Parts should be dried in humid conditions to prevent rusting. Parts should be painted as soon after cleaning and coating as possible.
Advantages
HP Phosphate has better flash rust protection than many other products designed for the same application. HP Phosphate may be used at room temperature if needed.
In addition to coating steel, this product also deposits a light coating on aluminum and galvanized surfaces.
It is used at exceptionally low concentrations, therefore has lower chemical discharges and less cost.
Disposal
Follow all local discharge regulations before putting this product down a drain. Because of the short contact times and the one-pass nature of HP Phosphate, heavy metal buildup or buildup or grease or oils are not generally a problem. Although the ingredients of HP Phosphate are biodegradable, any detergent or cleaning chemical may have problems depending on local codes.
