It’s a critical component of getting a return on your investment.

The paint spraybooth in a collision repair facility represents the single largest capital investment for the owner and its effective operation is one of the biggest concerns for every shop. A top quality spray and cure spray booth can cost over $100,000 so maintaining them is critical to make sure that investment pays off. Two experts in the field of spraybooth maintenance are Don Ives, “The Booth Man” and Keith Hayward, “The Filter Guy”. Don Ives services spraybooths throughout southern Ontario and Keith Hayward provides the filters that every booth requires. Here is what they have to say about effective spraybooth maintenance.

Air Flow

Spraybooths are generally designed to meet or exceed code at 100 feet per minute of air flow. This protects the painter by drawing overspray away from him and ensures that overspray is drawn to and trapped by the exhaust filters. With clean fans, stacks, and filters, all standard spraybooths will run with good air flow. When filters are clogged, either with dirt/dust at the air intake (ceiling) filters or with overspray it the exhaust (pit) filters, air flow is restricted. Other factors that effect air flow include overspray build up on fan blades and inside the exhaust stack.

Booths work best when they are running at slightly positive pressure. They should basically be balanced between air entering and exiting the booth, and by making them slightly positive, the extra air will be forced out any cracked seals around doors or any small gaps that inevitably exist. If a booth has negative pressure it will be drawing unfiltered air though those same cracks and gaps and end up landing on the car and fouling the paint job.

In downdraft spraybooths a good diffusion media filter is required. These filters usually come in blanket form and cover the entire ceiling of the booth. This type of media diffuses the air flow, forcing it to flow evenly across the face of the entire filter, creating a nice uniform air flow throughout the booth. Without diffusion media, the air would blast down through the booth under the air source, while the rest of the booth remains stagnant.

Air Quality

Clean air is critical to a good finish. Diffusion media is very efficient so it will stop all the dirt and dust that will cause problems in the finish. The key to good air quality is to ensure that the air coming into the spray area is forced through the filter.

When a booth is in the purge cycle, especially when it involves waterborne coatings, temperature must be maintained at the paint manufacturers recommended temperature.

Regular Maintenance Intervals

Most booths require a good maintenance cleaning every 1000 hours (or less) of operation depending on use. The filters need to be changed out when a service/cleaning is done and also in between service as required. A basic service includes cleaning the stack and the fan, the exhaust pit and changing the filters. Also cleaning the burner, greasing motor and bearings is required. A more thorough service also includes things like replacing door seals, cleaning light fixture glass, replacing light bulbs, cleaning booth walls and floor, re-caulking any gaps in the booth and anything else to bring it back to ground zero.

According to Don Ives, the Booth Man, “I find the biggest problem with maintenance is that most shops over extend the scheduling of booth cleaning. It is like car maintenance: if it doesn’t get done the car won’t perform to its optimum level.”

Waterborne Finish and Overspray

Waterborne coatings present two problems for spraybooths. First of all, the time, temperature and air flow required for effective curing of waterborne coatings all need to increase. Many spraybooths have now been retrofitted with air accelerators to improve air circulation.

Ives notes that “Air flow is critical to a good finish. It a booth is not maintained by cleaning and changing filters regularly, the new waterborne coatings are more likely to glaze over or sag. Air accelerators help with these problems but they do not eliminate the need for a well maintained booth.”

Secondly, waterborne overspray particles are comparatively huge, so they clog filters faster. “If a solvent based particle is the size of your fingernail, a waterborne particle is the size of your fist,” says Hayward. “Ideally exhaust overspray collection filters load from back to front, or bottom to top in a pit. With large waterborne particles the same filters will “surface load” or “blind.” When a filter blinds over, only the first 10 percent or so of the filter is being used. Over the years shops have trended towards more expensive filters that depth load, last longer and are changed out less frequently. However with filter blinding, generally the least expensive filter is best because it will need to be changed out much more often. By changing cheaper filters more often, material costs will be about the same but unfortunately labour costs and “hassle factor” will increase.”

Waterborne clearly presents challenges to spray booth maintenance but with regular booth cleaning, improved air flow, and more effective exhaust filters, those problems are solved.