Incorrect application of the paint often causes air bubbles to be trapped in the paint and causes foaming or depressions when dried. If the paint is applied too fast, large quantities of air are trapped into the paint by the sloppy brushwork. When using a roller, it is important to use a cover with the recommended nap. Using a cover with a higher grade nap leaves your paint looking rough and uneven, while a lower nap traps air in the paint as it is being applied. Excessive brushing often causes air to be trapped within the paint as it is being spread too thin, making the paint dry faster and trap the air within the finished product.
Applying paint to a low quality or unsealed surface leaves you with a rough texture as air bubbles get trapped between the surface and the paint. Before painting a surface, a sealer or primer should be applied. Depending on the type of surface you are painting and the type of paint you will be using, you need a certain type of sealer. All applicable types of paint are usually listed on the instructions of the sealer's can. Applying a sealer minimizes the chance of air bubbles getting trapped between the surface and your paint as well as the number of coats you must use to get a rich color.
Painting during extreme temperatures often causes the paint to either dry quicker or freeze. Having your paint dry quicker might seem like a benefit; however, this often makes the paint dry before the air bubbles have enough time to seep out of the paint, leaving your final product with unprofessional pock marks. Each can of paint has a recommended temperature to paint in printed on the label.
Allow the sealer to dry thoroughly before you begin painting. Once the sealer is dry, sand it down to get rid of any uneven edges and bubbling. Let the dust settle and wipe down the surface with a wet towel before you begin painting. Stir the paint slowly before you begin painting to allow any large air bubbles to seep out of the paint. When painting pay attention to the surface of the paint you are applying. If you notice excessive bubbles then slow down the application process.