Aerosol consists of propellant and the product itself, which can be in the form of a liquid, foam or semi-solid. Valve modifications have improved the spray pattern of aerosol paints; some permit spraying in any position, even upside down to touch up water spots on ceilings.
There are three kinds of propellants: hydrocarbons (liquid propellants), carbon dioxide (a compressed gas) and dimethyl ether.
* Hydrocarbons are effective as propellants because they turn to vapor as the product is used and fill the void left by the decrease in product.
* Carbon dioxide does not maintain a constant pressure, so it is best recommended where a coarse, wet spray is needed and where the distance to be sprayed is short.
Inhalation of substantial amounts of the propellant gases may be harmful to health. Caution customers that aerosols are effective and safe--as long as the product is used in well-ventilated areas. For most aerosols, instructions on the can make usage easy, but paint is different because kinds and qualities vary greatly.
The first place to evaluate quality in aerosol paints is on the can--by noting the percentage of paint to propellant. The fill ratio used by manufacturers will vary. So will the kinds of propellant.
The most common propellant is a lightweight hydrocarbon. A common fill ratio for a hydrocarbon is about 77 percent/23 percent. That means a 16 fluid oz. can would contain 10 ozs. of paint by weight and only 3 ozs. of propellant.
The formulation of the paint itself can vary. Some formulas cover better; others last longer; some provide a brighter gloss.
Aside from those differences, the type of finish and length of wear are used to classify paints used in aerosols. Generic terms such as "enamel" and "lacquer" are used, but they also encompass a variety of film-forming resins with differing characteristics.
Primers, stainless steel coatings, faux finishes, antislip sprays, rust preventers and graffiti removers all come in aerosol form.
Spray-on latex paint is available that is safe to use indoors or outdoors, resists scratches and cleans up easily with soap and water. It can be applied to wood, metal, wicker, clay, plaster and plastic materials.
There are also three different spray-on glass finishes. The transparent paint can be used to add color to glass making it look like stained glass. The semi-transparent paint gives a frosted glass look. The reflective finish can be used to create mirrored finishes.
Numerous cities and a handful of states have enacted legislation to regulate aerosol spray paint, either prohibiting sales to minors or requiring spray paints to be locked up. Make sure you are familiar with any requirements in your area.