- Maximizing Aerosol Paint Performance - Eastwood Tech Library
Maximizing Aerosol Paint Performance
Naturally, you want to begin by purchasing high-quality aerosol paints. The best aerosols use a higher-quality paint, cover more quickly, and often feature a fan spray nozzle. "You get what you pay for" holds true for aerosols, too. Generally speaking, stick with the more expensive paints sporting brand names you know and trust. These will cost you anywhere from $5 to $10 per can, but are well worth the investment.
There is usually a reason why the $1 to $2 cans are so inexpensive. They tend to be thinner paints that run very easily, and thus do not cover very well. You'll most likely need additional coats to obtain the same coverage as you would obtain from one pass of a more expensive, high-end brand. In the long run, inexpensive brands translate into significantly more effort with a similar expense as you would have incurred had you begun with the better aerosol in the first place. Even then, you probably will not achieve the same caliber of results.
Please keep in mind we are not condemning all inexpensive aerosol paints, but it has been our experience that a general statement may be made about them. It is recommended that you keep in mind the results you are striving to achieve. The better the result you expect, the greater your investment is likely to be. Of course, be sure to read and follow all manufacturer label instructions and precautions.
The importance of proper preparation cannot be overemphasized. This is the step most likely to be overlooked, yet it is critical to the quality of the end result. Following most label instructions involves one or more of the following cleaning steps:
Stripping the Existing Coating
- Remove the previous coating with a 5" Cleaning Disc, 7" Cleaning Disc, wire wheel, or by abrasive blasting.
- Remove any corrosion with Eastwood Fast Etch. If you removed the previous coating via abrasive blasting, then you can remove the corrosion with this method as well. If the rust can still not be removed, refer to the Priming Over Surface Rust section below.
- Thoroughly clean the part with PRE Painting Prep, Eastwood Metal Wash, or repeated wipes with lacquer thinner or acetone.
Painting Over An Existing Coating
- If the previous coating cannot be easily removed, test by cleaning a small area and apply the new finish over the old. Determine if any unfavorable reaction or undesired look has occurred. If you can live with the results, make sure that the old paint is solid, and free of any dirt, silicone or oil. Next, scuff the part with 320-grit sandpaper to allow for greater adhesion of the new finish to the old.
- Spot-prime low spots (a chip or drop in the metal) and any part of the surface which may be bare. Sand with 320-grit sandpaper to assure a smooth, even surface. (Be sure to test the primer for compatibility with the surface you'll be painting. Look for an unfavorable reaction such as wrinkling or lifting.)
The application of a primer coat prior to the final finish is recommended for most paints. Primers are designed to enhance the final finish's durability and adhesion to the stock.
Priming Over Surface Rust
- Remove any grease, wax or oil contaminants from the surface to be painted with PRE Painting Prep, Eastwood Metal Wash, or repeated wipes with lacquer thinner or acetone.
- Use a wire brush to remove loose rust.
- Apply two medium coats of Rust Encapsulator, either with a brush or spray.
- Allow the Rust Encapsulator application to dry for 36 hours if an enamel paint is to be applied; 72 hours if a lacquer-based finish is to be applied.
- After the proper drying time, scuff the surface with a 320-grit sandpaper.
Priming Bare Metal Surface
- Remove any grease, wax, or oil contaminants from the surface with PRE Painting Prep, Eastwood Metal Wash, or repeated wipes with lacquer thinner or acetone.
- Apply primer where not expressly prohibited. We suggest using Eastwood Self-Etching Primer.
Please note: Eastwood Self-Etching Primer is NOT recommended for use on surfaces that will reach temperatures above 180°F, nor as a primer for Eastwood's Chassis Black Aerosol Paint.
Be sure you are working in a well-ventilated area. It's generally best to apply aerosols at a room temperature of between 65-95°F. The optimum humidity level is below 50%. Painting in higher humidity can cause the paint to "blush", a condition caused when moisture in the air condenses on the paint as the paint is drying.
- Shake the aerosol can thoroughly. Usually, one to two minutes of vigorous shaking is required to get the contents mixed well enough for applying. You'll know the paint is ready when the mixing ball inside the can begins to easily rattle while you are shaking the can.
- Test spray. Should the can's spray nozzle be clogged, do not attempt to unclog it with a needle. This will likely cause damage to the nozzle, and ruin the spray action. Instead, carefully remove the nozzle from the aerosol can, and soak it in solvent. Lacquer thinners and acetone typically make for good solvents. This will restore the spray head to its original condition. Replace nozzle using a twisting motion to avoid damage to the sealing O-ring.
TIP: Save old aerosol nozzles so that you have a selection from which to choose should you ever need a replacement.
Always have your work set at a height convenient for you. When spray painting, a clothesline works well and will make it easier to for you to attain complete coverage of your workpiece.
- Mask off any areas not to be coated.
- Hold your aerosol can in an upright position whenever possible. Be sure the nozzle is facing the object to be painted, not your face. Depress the nozzle only with the tip of your index finger. Using any other part of the finger may put it in the way of the spray, affecting the spray's pattern. You should also maintain a proper distance between the aerosol can's nozzle and the object being coated. This distance normally is 8" to 12".
- Spray any recessed areas first. The use of delicate, short bursts often helps.
- When coating the rest of the part, keep the nozzle parallel to the surface, using long, steady, even strokes. Keep the can equidistant from the part throughout the process. Don't arc your stroke. Instead, move your entire arm from the shoulder.
- Overlap coats to assure even color density. Overlap each pass by approximately 50% of the total width of the spray. In other words, with each pass, you are covering new surface with 50% of the width of the spray, and the other half of the spray is re-coating what the previous stroke painted. Do your best to not stop your stroke while in the middle of the part. Keep a wet edge by beginning the job at one edge of the part. Spray horizontally to the other side. Begin at the top of the piece and with each pass of the spray, work toward the bottom of the piece.
Follow these steps when you are finished painting.
- Invert the aerosol can, and spray it in a safe direction (into a trash can, for example) until there is no more paint spraying from the can, just air. This action serves to clean the nozzle of any paint residue which would dry and potentially clog the nozzle.
- For maximum shelf life, store all aerosol cans right side up in a warm, dry area. An environment with a temperature of anywhere from 55-85°F is ideal.
- Caution! If water-based aerosol products are allowed to freeze, they may be ruined.