HVLP Spray Techniques

HVLP paint and clear coat finishes can be greatly enhanced by increasing the number of techniques used during material application. Although most modern materials can be applied using a conventional left-to-right movement of the spray gun, there will often be circumstances where the technique can be changed to achieve better coverage, different shades and varying textures. More often than not, different techniques are used as a means of troubleshooting a paint finish, and these are adopted by professionals on a daily basis.

Conventional Application

Apply paints and clear coats by activating the material with a compatible hardener and thinner before transferring to the HLVP spray gun. Position the gun at a distance of 6 inches from the panel, and ensure that the nozzle sits at an angle of 30 degrees to the face of the surface, which is vital for achieving a consistent fan of atomized material. Move the arm at a steady speed in left-to-right movements, reversing the procedure as the gun comes back across the panel on the next application. Remember to cross each movement by 30 percent to ensure paint edges merge.

Eliminating Runs and Sags

Increase the spraying distance to approximately 10 inches if consistent problems with running or sagging paint are occurring. Twist the fluid needle retaining screw inwards, using a clockwise direction, to reduce the amount of material being atomized. Compensate for the drop in material volume by moving the arm slower when the gun is working across the face of the auto body panel. Always look across the panel in good light while painting is in progress to ensure a wet, even coat is achieved.

Crossing Coats for Uniform Coverage

Use cross-coating techniques to ensure full paint coverage has taken place when using metallic materials. Apply the first two coats using a conventional application method, leaving a short 10-minute period between each coat to allow for curing. Reduce the air pressure of the spray gun to approximately 8 pounds per square inch at the air cap, and open the fluid needle retaining screw fully by turning in a counterclockwise direction. Hold the spray gun 18 inches away from the panel, and apply a light even coat using left-to-right arm movements. Once the panel has been covered, maintain the same spraying distance, but use up-and-down arm movements to cross the coats together. This method allows for the ideal color and metallic content distribution.

Painting the Ideal Bonnet

Remove the bonnet from the vehicle once it has been prepared, and place it on a stand so that the surface is completely flat. Increase the spraying pressure to 12 pounds per square inch at the air cap, and wind out the fluid needle retaining screw fully. Move the arm closer to the panel so a distance of 4 inches is maintained at all times. Pull back the trigger of the HVLP gun, and move the arm in faster, single movements over the face of the bonnet to achieve a flat, sealed first coat. Let it cure for five minutes before applying a slower, heavier coat over the bonnet from a distance of 6 inches, which will promote material flow as the bonnet dries and will result in a perfectly flat, high-gloss finish.