Bank on paint booth basics

One of the truths repairers operate their businesses by is that serious problems frequently have relatively simple causes. Consider the following case of an owner who expanded his operation to a second site with some major issues in its paint department.

The department was performing a number of re-dos, which usually involved polishing out and repairing paint imperfections. A further investigation revealed that the problem was long standing. The shop's previous owners had simply accepted the extra repair time as normal.

Wanting to quickly resolve the issue, the owner asked his chief painter and a rep from his paint vendor to spend an afternoon reviewing the shop's painting procedures to locate the source of the re-dos. They found that the painters' spraying techniques were proper, as was the prep work, product mixing and most other procedures. That left the spray booth as the prime culprit.

An investigation turned up cheap, ill-fitting filters. Further, employees were regularly leaving the booth doors open between jobs. Once these two areas were addressed, the re-do issues disappeared, and the paint department's production numbers improved.   

Attending to small details can produce big results for shops. Nowhere is this more true, arguably, than in your spray booth, where straying from recommended maintenance and usage can result in expensive contamination problems. Let's look at all the details you should be managing with help from two booth manufacturers — Accudraft and Global Finishing Solutions (GFS).

Focus on filters
One of the keys to spray booth operation is consistency of airflow. For the booth to operate properly, airflow must be balanced and consistent to allow paint products to be sprayed and dried evenly and to remove any contaminants.

Airflow balance is upset most often by poor filtering, which typically is the result of using low-quality filters or not replacing booth filters according to the manufacturer's recommendations.

To address the first of these issues, shops should only use high-quality filters — those high-grade versions recommended by the manufacturer. Lower-grade filters affect airflow balance because they don't provide the efficiency and the correct diffusion necessary to provide consistent airflow, which is crucial for removing particulates and other pollutants. Sometimes they affect airflow balance simply because they don't fit properly.

To ensure these filters do their jobs effectively, they need to be replaced routinely. When they aren't, contaminants can build up on their fibers and plug them up, allowing overspray to build up on the exhaust fans and upsetting the booth's airflow.

Setting a replacement schedule involves factoring in the booth's engineering, workload and products being used. According to GFS, filters typically need changed when the final resistance (specified by the booth manufacturer) has been reached. Shops determine the resistance by checking the inclined-tube, U-tube or gauge-type manometers on the booth and referencing the operator manual. 

Before setting a replacement schedule, speak to both the booth manufacturer and your paint company reps, who will have the most comprehensive information on how to effectively use their products in your booth. They also can help you set up internal systems that will ensure your managers and employees maintain the filter replacement schedule.

Note that before disposing of waste filters, you must determine whether they could be considered hazardous waste. Consult with your filter supplier and local authorities for assistance in properly characterizing and handling waste filters.

Two spray booths can double your paint production, unless you allow poor booth maintenance to affect the quality of your finishes. Photo courtesy of Lefler Collision and Glass

Clean up your act
Spray booths require regular cleaning to remove contaminants and overspray that inevitably collects on floors, walls and other surfaces. Even when a booth runs at peak performance, it still can't remove all particulates. When any remaining overspray dries, it becomes airborne and can end up on your subsequent paint jobs.

Ideally, you should be cleaning the booth every day, especially if the booth is in regular use. If you can't clean daily, try to schedule a cleaning every other day. At the very least, clean the booth once a week. Just remember that the more the booth is used, the more overspray collects. During periods of high use, you'll need to clean more often. Again, this schedule is something you should discuss with the manufacturer and your paint vendor. 

Just as important as your cleaning schedule are the equipment and products used.

GFS recommends using a sponge mop and solvent-based materials to break down the paint on the booth floor and walls. They also stress never using a cotton mop, as it will leave fibers behind. Stick to lint-free mops to remove excess debris and overspray buildup.

Also, make sure the ventilation system is in operation when you use solvent-based cleaning materials. For a deeper clean, try pressure washing booth walls, floor and the pit.

Always examine booth exhausts for paint buildup. Old paint deposits can build up in the exhaust fan, duct and plenum, reducing booth operating efficiency. Inspect the entire system for potential problems before they can occur.

You'll also need to do some cleaning beyond the booth itself, especially on paint guns and air hoses where overspray can collect before it flakes off and ends up in your finishes. Clean these areas and the insides of air hoses, since paint can collect there as well. Set a regular cleaning for your equipment, and only use lint-free wipe cloths. When you move this equipment into the booth for work, be careful not to drag hoses across dirty shop floors and bring in contaminants.
 
On a safety note, be cautious using a shop vacuum to eliminate dust and fibers in your booth. These materials are flammable and combustible. Heat generated by the vacuum motor can ignite them. If you decide to use a vacuum, make sure that it is approved for hazardous locations.

Closed-door policy
Since open doors invite particulates into a booth, keep the doors closed at all times, except when performing necessary tasks, like loading or unloading parts.

When the doors must remain open, even for short times, keep the booth fans operating to maintain minimal pressurization. This prevents any particulates entering the booth from being transported throughout it, where they stand the greatest chance of damaging a paint job. The influx of contaminants is related to booth engineering that is designed to remove dangerous fumes.

A booth's exhaust stack damper remains partially open when the fans are off to prevent the accidental buildup of VOCs or other noxious vapors. This creates an updraft of air that continually pulls air through the spray booth, commonly referred to as a chimney effect. When the booth doors are open, these small drafts of moving air carry damaging particulates, especially fibers, into and throughout the booth where they may become a source of contamination.

To help employees stick to a closed-door policy, limit traffic in and out of the booth. Permit only authorized employees in the booth, and don't allow employees to store equipment or products in the booth. Using your booth for storage means the doors will be opened more often. Also, stored items can carry in and collect damaging particulates.

On a related note, makes sure the doors and the rest of the booth are properly sealed. Seal the entrance and exit doors, access doors and concrete floors, along with any other areas where contaminants may pass in the booth. If necessary, caulk ceiling frames, fire sprinkler openings, wall joints and all compressed air pipe openings.

Problem prevention
One of the best ways to prevent booth contamination is eliminating possible contamination sources that will go in the booth or near it.

Start by mandating that all personnel are clothed with lint-free garments while in the spray booth, and ensure that those garments are not worn outside of the spray booth to perform other tasks. When these garments are worn inside of the spray booth, air passing across the surface creates a mild static charge to make it a magnet for every piece of lint or fiber close enough to attach. If possible, install a changing room attached to the booth or use an attached paint mix room for this purpose. Always store your painters' suits in a clean area.

If possible, perform all your prep work outside of the booth in prep stations. Performing tasks in the booth, such as using compressed air to blow off the parts prior to painting, can free up enough contaminants to damage paint jobs during an entire day. If this kind of work must be done inside the booth, give the booth about an hour or so of run time to change out the air through the filters. That should be enough time to fully remove the contamination. Then, be sure to tack off the parts prior to painting.

Keep in mind the time you can lose by having the booth filter out contaminants from prep work. If you don't have enough space to do your prep work, consider adding room. The payoff in improved paint times is well worth the investment.

Never perform any sanding in your booth. If your shop uses a wet sanding or buffing operation in the same general area, isolate these operations by using curtains and pressurizing the painting area with an air makeup system.

These recommendations should head off the majority of issues you might have with your spray booth. The good news is they're relatively simple to implement and maintain, and their results will show up immediately in your shop's number and product quality.

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