It’s easy to overlook your spraybooth’s filters, but maintaining them is crucial to working with waterborne. Here’s why.

Filters: the little things that can save you thousands of dollars a year.

Wow, what a crazy four-year journey this has been, running door to door into collision centres. I have been in over 400 facilities from East Toronto to the Hamilton Mountain. I have been in facilities where you could eat off of the floor, and then into shops that I would not take my dog to for a haircut.

And do you know what? Eighty per cent of the shops push their filters too far. They consistently have to compound paint jobs and do not even realize how much time, money and production they are losing by not having clean filtered air entering their paint booths.

Do you realize every medium-sized compound job loses you about two hours of production, plus pads, electricity, compound and waxes, etc?

Not only that, but that prepper could have had those two hours to get the next vehicle ready for the painter.

Well, what does all this mean to you? How can you save time and money, and get better paint jobs?

First of all you must keep air flow equal in the booth, the same amount of air coming into the booth as the amount of air flowing out of the booth.

To maintain a good air flow, let’s begin with a look at intake filters (either the ceiling filters in a downdraft booth or the door filters in a cross-draft booth).

When the intake of your booth starts to get plugged you will fall into a negative booth pressure and the doors get easy to open. Air flows along the path of least resistance, so if you have a negative pressure booth, it is drawing in dusty air from the facility that is ending up on the car you are trying to paint.

The ideal situation is to have a booth that is “slightly positive” so if there are any cracks the air will escape, not enter the booth.

Good intake filters will become more efficient as they load so as to prevent dust and dirt getting through. This also creates more restriction to air flow and the negative pressure situation outlined above. So, bottom line is that you need to force the air through the intake filters to keep the air in the booth clean, so when they get loaded less clean air and more dirty air is circulating through the booth.

When the filter’s visibly loaded and your doors fly open from the negative pressure, it is time to change the intake filters.

Now let’s talk an even bigger challenge: waterborne and your exhaust filter media (usually fiberglass) plugging up in half the time and because of surface loading only the top .5” of the filter is being used.

What’s up with that?

Well here is the answer: hold up your hand in front of you and look at your thumbnail. Let’s just pretend that your thumbnail is the size of a solvent-based molecule. Now make a fist—that is the size of a waterborne molecule.

Therefore in the molecule world, waterborne is massive. It plugs filters fast.

As the filter blinds over with paint, it allows less and less air to flow through the booth. Less air flow causes paint to linger in the air and slows down drying time. Most types of exhaust filters act the same way as intake filters in that they become more efficient and restrictive as they load. This is referred to as impaction filtration.

A better way to go in the new waterborne world is with impingement filtration.

Impingement filters (accordion style or baffle box style) maintain a constant air flow while loading. This is because the offset holes in an impingement-type filter force the air to change direction and exit the filter while the overspray sticks and builds up on itself.

As long as the holes remain open, air will flow at a constant rate so that good air flow is maintained over 95 per cent of the filter’s life.

If you are concerned about efficiency, a second-stage downstream media (usually polyester) can be used and even changed out at a different frequency than the primary impingement filter (say, every other time).

Clean filters make for clean paint jobs. Every time you push filters too far you pay in lost time and productivity. To make money and speedy production, clean filters are a must.

For more information and a booth inspection you can reach Keith Hayward, “The Filter Guy,” at 416-801-5218.