MRO Today - Spray success with aerosol products

Spray success with aerosol products
by William Goodwin

Back in 1962, the Packaging Institute of America voted the aerosol container the "finest package conceived in the first half of the 20th century" for its effectiveness, minimal waste and convenience. Over the years, aerosols have proven themselves in many applications. They’ve made dispensing a multitude of products easy and effective.

But in the second half of the century, aerosols have gotten a bad reputation, which, given the changes in aerosols, is largely undeserved.

From environmental concerns to performance problems, new aerosol products address many of these concerns.

Tips to select the right aerosol
Selecting the right aerosol product for most applications is rather straightforward, while some applications require more thought. Answer these questions to select the right aerosol product for your application:
• Is flammability and/or flash point a concern?
• Will the product or propellant react with plastics or painted surfaces?
• Are there any health concerns with the product?
• Are there any special EPA-mandated disposal requirements?
• What corrosion protection is provided vs. what’s needed?
• Does the aerosol contain chlorinated solvents in the propellant, and how will that affect the workpiece?
• Is the environment or workpiece particularly moist, dry, dusty or dirty, and how will that affect the application of the aerosol product?
• Will high or low temperatures affect the product’s performance?
• What surface preparation will be required before you can correctly apply the product?

Spray tips
• Avoid using aerosol products when the temperature is above 120 degrees F or below 0 F. Some can perform well at these extremes, but most will not perform satisfactorily if too warm or too cold.

• To get the best aerosol performance, make sure the arrow on the nozzle lines up with the mark on the container.

• When you must spray with the can upside-down, use an aerosol that’s designed for this purpose.

• To insert the small tube supplied with some products to spray in a hard-to-reach place, remove the nozzle, then press the tube into the nozzle’s orifice.

• Vigorously shake all products before and during spraying.

• Before spraying, test the spray pattern on a scrap surface to get the "feel" of the can and to make sure it is spraying properly.

• To prevent paint runs or sags, start and stop the spray off the work and do not attempt to cover with a single coat. Follow the directions about how far to hold the can from the workpiece (typically 8 to 10 inches).

• If the aerosol sprays intermittently, rotate the nozzle one-quarter turn.

Aerosols and the environment
First, the environmental concerns: Chlorofluorocarbons (CFCs), which have been implicated in causing ozone layer depletion, were the propellant of choice in aerosols. Since CFCs were banned for propellant use in 1978, hydrocarbons, carbon dioxide or nitrous oxide are used as propellants in almost all aerosols.

Aerosols have also been accused of being environmental bad guys because the products they dispense often contain volatile organic compounds (VOCs). Varying levels of VOCs can be found in some aerosols (for example, paints, solvents, degreasers) and manufacturers are working to reduce them. The EPA reports that less than 1 percent of all VOCs emitted into the atmosphere come from aerosols, while car exhaust contributes 70 percent.

Aerosol performance
The second most common concern relates to performance. Most performance problems are caused by improper care and use.

Clogged nozzles tops the complaint list but can be almost eliminated if you turn the can upside down and spray a short burst to clear out the valve and nozzle after every use. This is the aerosol equivalent of cleaning the brush after painting.

To clear a clogged aerosol nozzle, remove it from the can (pulling straight up) and run a knife blade or fingernail through the tiny slit at the end of the stem, then clear the spray orifice by inserting a pin or needle. Some manufacturers recommend clearing the clogged nozzle by soaking it in ether.

Safety and disposal points
Always wear eye protection and use aerosols in well-ventilated areas. Fumes from the product mist may cause a flash fire, so keep aerosols away from open flame. Keep metal aerosol cans away from electrical ignition sources and battery terminals. Some aerosols have a warning on the can that states, "Do not use on energized equipment." This warns of the chance that the sprayed product could conduct high voltage back to the can and into the hand of the user. CRC, a manufacturer of industrial aerosol products, says this warning should apply to all aerosols.

Unless subjected to high temperatures, aerosols will not explode. If punctured accidentally, the contents may be blown out of the can so quickly it might seem like an explosion. According to the Plasti-Kote Company, cans may burst if they are subjected to temperatures higher than 130 degrees F.

Read the Material Safety Data Sheet (MSDS) on each aerosol product before using it. MSDS informs the user of possible safety concerns and instructions on how to use the product. It also offers proper disposal procedures.

Information for this article was provided by the Consumer Aerosol Products Council, CRC Industries Inc., ITW Dykem, LPS Laboratories Inc., Plasti-Kote Co. Inc., Pressure-Lube Inc., Rust-Oleum Corp., STS (Division of Tech-Chem) and WD-40 Co.

This article appeared in the February/March 1998 issue of MRO Today magazine. Copyright, 1998.