Lower Acid Iron Phosphate Conversion Coating
LH Phos is a cleaner/conversion coating product for high-pressure wands. It deposits a phosphate coating which improves paint adhesion and corrosion protection of steel. It cleans and conversion coats at the same time.
Using LH Phos allows you to prepare large fabricated items for painting. It is a steel only product and will clean aluminum and galvanized surfaces but will not deposit a substantial coating thickness on these metals.
It removes very light rust and often eliminates the need for sand or media blasting.
Although normally used at elevated temperatures, the product will deposit coating at room temperature. Normally, higher temperatures provide better cleaning and greater paint adhesion.
Use
HP Phosphate operates at concentrations of 1-2% by volume. Typically, at 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. Sometimes several passes over the metal surface may be required. At room temperature application requires a longer contact time.
The parts can be air-dried but acceleration by an air blow-off or an oven helps prevent flash rusting. Parts should be forced dried in humid conditions to prevent rusting. Parts should be painted as soon after cleaning and coating as possible.
Advantages
LH Phos has a lower amount of acids than similar products. Because of its low acidity level it is not subject to DOT hazardous shipping regulations. It is shipped by FedEx rather than requiring a more expensive trucking firm. LH Phos has better flash rust protection than other products. It also can be used at room temperature if needed.
LH Phos has a higher pH (lower acidity) than most pressure phosphate products. It is easier and safer to dispose of down the drain. If discharge into a sewer requires neutralization very little neutralizer is needed. Often no neutralizer will be needed.
It is used at low concentrations and therefore has lower chemical discharges and less cost.
Disposal
Follow local discharge regulations before putting discharging down a drain. Because of the low acidity level LH Phos normally does not build up and heavy metals that may create a hazardous waste. Build up of grease and oils are generally a problem. Although the ingredients of HP Phosphate are biodegradable, any detergent or cleaning chemical may have problems depending on local codes. Although the acidity level is as low as possible with a product of this type, pH neutralization may still be required depending on local regulations.
