How to turn your garage into a paint booth
What image first comes to mind when you hear of a car that was painted in a garage? Do you envision a flawless finish that is worthy of a high-caliber show car? Probably not and it depends on paint protection your are using. Do you imagine a hulk with questionable bodywork and more than an occasional flaw in an unremarkable topcoat? Maybe. The truth is, the paint booth or where a car is sprayed has much less to do with the end result than the expertise of the guy behind the bodywork and paint gun. As we’ll illustrate on the following pages, remarkable results can come from a most humble environment, a revelation that is equally important to both the do-it-yourselfer and his checkbook.
Right up front, this isn’t a story that’s going to teach you the ins and outs of paint and bodywork. We’ve run several articles in recent months that are oriented toward those disciplines, but our objective here is to show you how one expert gets stunning results—not from a high-dollar paint booth, but out of a nondescript 25×30-foot garage.
No doubt, Dale Knutson is truly a master of his craft after laboring some 30 years in the industry, and, after watching him at work, we wonder if he couldn’t lay down a perfect finish in the midst of a Saharan sandstorm. During his career, Knutson has at times worked for commercial collision shops and at other times right from his home garage. In between, he’s churned out some pretty cool garage jobs for himself and friends, and we figured to glean some helpful hints by looking over his shoulder in the paint booth for a day.
One thing we picked up on right away: Do not misconstrue a garage paintjob for a cheap paintjob. Expertise doesn’t come cheap unless you possess it yourself, and you’ll pay for professional quality work no matter where it’s done. That said, a guy like Knutson—essentially a one-man show who has a lot less overhead than a big-time shop—may be able to complete a job for less overall cash. Nevertheless, the old axiom “you don’t get something for nothing” is definitely true here. To be sure, what doesn’t change based on the location of the work is the cost of materials. Depending on the paint system and color of your topcoat, materials cost can be tremendous. “A few years ago, I did a custom Mustang using a top-of-the-line three-stage product line, and the materials alone were right at $5,000,” Knutson says. Of course, this is one end of the spectrum, but it’s a point worth illustrating.
“Conversely, a much simpler solid-white hue using a quality two-stage product could be more in the realm of $600 for materials, but it all depends on the specifics.” We’ve recently covered worthwhile paint systems that can be had for considerably less, so if you have the ability to do it yourself, yes, a garage paintjob can be cheap. Again, it all depends on your situation and skill set.
Home Garage Paint Booth: The Space
As we mentioned earlier, Knutson’s garage measures a modest 25 by 30 feet. There’s some accumulated clutter after 30 years of use, but the majority of the space is usable. We’d consider the detached nature of the structure mandatory for keeping fumes away from living spaces, one of several safety considerations we’ll focus on a bit later. Winter temperatures can fall to around freezing, so Knutson uses a home furnace to heat the space when required—again, bringing up safety issues that need to be the foremost consideration in your planning.
Beyond the furnace, Knutson’s equipment is basic but high quality. He purchased a U.S.-made, 5hp, two-stage air compressor in 1977 that’s still running strong today, and it’s equipped with an 80-gallon tank. He’s confident a 60-gallon unit would provide plenty of capacity but would otherwise advise similar specifications. We expected to see some fancy air-drying equipment in use, but after tracing the air line from the compressor, up the wall, across the ceiling, and down to a simple water trap, we realized there’s nothing special going on here. “I’ve never had a problem with water in my air lines,” Knutson says. “I just do what works for me.” Obviously what really works are his quality Sata and Iwata spray guns—one for primer and paint, the other for clearcoat. In terms of the painting equipment per se, this is pretty much it—simple, huh?
Preparing the Space
Again, we were surprised at the simplicity that goes into Knutson’s preparation of the garage prior to painting. “First I sweep it out, then blow it out with air, followed by hosing down the floor and squeegeeing the water out the main door. I generally mask the car the same day, and then I close everything up and let it sit overnight to let everything in the air settle down. The next morning I go over the car with a tack rag and I’m ready to paint.” For some semblance of ventilation, Knutson generally sprays with the roll-up door open a couple of inches, and the main door cracked a similar amount. He finds that the airflow this creates is primarily at floor level and doesn’t introduce debris into the air. We asked about some kind of forced ventilation (a fan that might vent through the wall or ceiling), but Knutson doesn’t employ any such measure due to his concern that this would draw dust throughout the workspace.
When painting out of a space like this, you have to consider safety. It’s nothing to take lightly, and understand that what we’re describing here isn’t the end-all for safety precautions. We’re simply relating how one garage painter does it, bringing up some food for thought, and laying the responsibility for your personal safety on you. Determine a best course of safe action for your given situation, and resist cutting any corners here.
At least two major safety concerns come to mind when painting: health effects that can occur from exposure to volatile chemicals (VOCs and the like); and the danger of fire/explosion. On the respiratory end of things, Knutson uses a simple half-mask respirator with disposable filter cartridges known as an air purifying respirator (APR). Supplied air respirators also exist in the industry. Is the simple respirator adequate? We encourage you to look into the subject thoroughly, including reviewing manufacturers’ specs and discussing your selections with your safety supply house.
As for the fire/explosion danger, remember that the majority of automotive finishes are flammable during storage and application and are clearly at their most dangerous state when in aerosol form. We’ve mentioned the need to heat the workspace in a cold climate, but the potential for a flammable atmosphere and ignition source is obviously of major concern. Knutson has a long-established system of precautions he’s comfortable with. First and foremost, the furnace is always turned off prior to spraying, not just with the thermostat, but also with a switch on the actual furnace unit. “When it’s cool out, I get the environment warmed up to temperature (roughly 70 degrees) for some time before I’m ready to spray. Then I switch off the furnace, apply my first coat, and leave the garage until the finish is dry. When dry, the fumes have largely dissipated and I can warm the place up again in preparation for further coats, followed by the same switch-off procedure.” Remember that many gas furnaces will have a pilot light running at all times, so carefully evaluate your given scenario and take appropriate precautions. Those of you who live in warm climates, be thankful.
In the end, we think many of our readers will be surprised at the kind of paint job possible in the simple confines of a garage. This doesn’t mean a paint booth isn’t preferable—it most certainly is both in terms of personal safety and ease of application—but it obviously involves considerable cost. Done right, you wouldn’t know a garage-painted car from a booth job if the two were displayed side by side. Could you do the same in a similar space? Given the right skills, the answer is, yes, you can.