Open the lid to the paint or the primer with a flathead screwdriver. Pour the entire container of paint into a clean bucket. If the paint is a primer, use one part hardener and one-part thinner to mix the paint properly. This means the primer has a 2:1:1 ratio. An equal amount of hardener and thinner must be mixed with a equal amount of primer. Pour an equal amount of hardener and thinner into the primer and mix thoroughly with a stirring stick.
Use a 1:1 ratio for base coat paints. Pour in one equal amount of thinner into the paint. For example, if you have 1 gallon of paint, mix it with 1 gallon of thinner. Mix the base coat paint and the thinner thoroughly with the stick.
Use the 4:1 ratio to properly mix clear coat paints -- two parts paint to one part hardener and 10 percent thinner. The 10 percent of thinner equals 10 percent of the two-parts clear coat or two-gallons of clear coat. Pour 2 gallons of the clear coat into a bucket. Pour one part hardener into the clear coat and then pour in 10 percent of thinner into the mixture. Stir the mixture thoroughly with the stick.
Remove the lid from the Wagner Power Painter and place it on a clean surface. Fill the sprayer up with the paint or primer mixture and secure the lid back on to the sprayer.