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Finishing Academy Paint Booth Training

Choose one of these Automotive Refinish Training Modules:



  • Spray Booth
  • Operating Practices
  • Filtration
  • Balanced Air Velocity/Pressure
  • Maintenance
  • Cleaning

2.2.5 Spray Booth

Often a frustrated shop owner will blame booth filter pads and media for finish contamination. Fine filter media does have synthetic textile fibers, but in quality pads these are firmly bound together with synthetic resin. The downstream side is also covered and the surface is bonded with a woven material constructed of continuous filaments. The chances of a filter fiber ending up in the finish are remote. Look in this section for ways to prevent more likely contamination in the paint booth.




2.2.5.a Spray Booth


Operating Practices


• Do not keep any unnecessary items in the paint booth. They collect dirt.


• Never sand inside the booth.


• Never move a car in or out of the booth without the booth running.


• Do not leave solvents, tack rags, air hoses or other things in the spray booth on bake cycle. The heat will release oils and resins in the rags.


• Remove plastic covers before baking. Heated plastic can stain or cloud the finish.

2.2.5.b Spray Booth




• Don't skimp on fine ceiling or plenum filters, pre-filters and paint arrestor filters. A quality filter provides high efficiency throughout its life, not just at the start. What's more, quality filters also provide the correct diffusion to prevent inconsistent airflow and turbulence.

• Change filter media when the final resistance as specified by the manufacturer of the booth has been reached. Check resistance with a U-tube, inclined-tube, or gauge-type manometer.


• A plugged filter throws the balance of the paint booth off and allows build up of overspray on some exhaust fans, like squirrel cage fans, diminishing the efficiency of the fan, creating vibration and sometimes causing the fan to fail.


• Change pre-filters often to extend the life of the fine ceiling or plenum filters and keep air plenum clean.


Pleated Pocket


• Change paint arrestor filters as required.


Proper paint arrestor floor filters
Uniform-loading baffle-type (top)
Combination Strainer / Baffle
Strainer-type (lower two)


• The filter should have the denser side at the bottom, or downstream. This applies to both ceiling and floor filters.

• The best way to assure correct maintenance is to have the booth or filter manufacturer do it.


• In inversion weather (conditions conducive to smog, fog and frost), atmospheric dust concentrations are often ten times higher than during normal weather conditions. Pre-filters and fine ceiling filters may become filled in a short time. Keep a set of replacement filters on hand.











These fine ceiling filters trap particulate down to 10 microns

2.2.5.c Spray Booth


Balanced Air Velocity and Pressure




Check the spray booth pressurization daily — more often if booth is used continuously.


• All measurements should be made with a non-averaging velometer.

• Measure at door handle height, completely around vehicle.


Key #1
Velocity of the Air









• Balanced air differential no greater than 20 ft./min. (From one side to the other)


Key #2
Balanced Airflow








2.2.5.d Spray Booth


Maintenance (After Hours)



• Ceiling frames
• Wall joints
• Fire sprinkler openings
• Compressed air pipe openings


• Entrance and exit doors
• Access doors

Allow cabin atmosphere to settle 2 hours prior to spraying

2.2.5.e Spray Booth


Cleaning the Booth


Regardless of how well your booth is engineered, it’s likely that eventually SOME overspray could collect on your spray booth walls, floor and other surfaces. Any overspray or dust in the booth can become airborne and land on your paint job. To prevent this from happening, your booth surfaces must be regularly cleaned. There are several methods for cleaning. It’s important to be sure that the equipment you use is suitable for the location and the material being cleaned.

Some shops use vacuums to clean a booth of stray dust and fibers, but there is reason to be cautious about doing so. Because you are vacuuming up flammable and combustible materials, sparks and heat can be generated by the motor in the vacuum, and ignite the material collected. If you decide to use a vacuum, make sure that it is approved for use in hazardous locations.
We recommend using a sponge mop and solvent-based materials to break down the paint on the booth floor and walls. DO NOT under any circumstances use a cotton mop, as it will leave fibers behind. The ventilation system MUST be in operation when using solvent-based materials. Booth walls, floor and the pit can also be pressure washed for a deeper clean.


Protecting Booth Walls


To protect the paint booth walls from overspray, we recommend using a booth spray wall shield. This spray-on wax coating protects walls for about six months, and then is stripped off. DO NOT use removable paint on the booth walls. It can flake off to introduce contaminants. What's more, it is difficult to remove all of it, which is unattractive.








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12731 Norway Road • Osseo, WI • 54758 • info@globalfinishing.com • 800-848-8738