Any experienced gearhead will tell you that a professional-quality paint job doesn’t happen overnight—it’s the result of hours of training, practice, and prep work.
And while that might dissuade a lot of folks from tackling a paint project themselves, the truth is, you can do a pro-spec automotive paint job in your home garage and—honestly—it’s a pretty straightforward process.
To help explain how, we sat down with well-known automotive paint expert Kevin Tetz for a recent podcast interview. If you haven’t seen him on TV already, Kevin’s the guy behind the Paintucation Automotive Paint and Body Educational Series of books and videos. So yeah, he’s the perfect person to talk to about this topic.
Though the interview was an hour long, we picked our 10 favorite questions from the conversation and summarized Kevin’s answers. Read the excerpts below and you can listen to the whole interview in our podcast series here:
10 Automotive Paint & Body Questions with Kevin Tetz
1. Why Does 1990s-era Clearcoat Peel & How Do You Fix It? (Reader Submitted)
“In the 1990s, most of the OEs started to go to a two-stage paint system, which is a basecoat, your color coat, followed by a clearcoat, which is the protection layer. So now, it’s not a single coating, it’s two layers.
“What happens is that clearcoat deteriorates and, as it ages, UV rays go through that layer and they oxidize, or deteriorate, the ground coat layer underneath the clear, causing it to separate and peel. Factories use minimum tolerances and they put just enough paint on there to last 36,000 miles.
“There’s no way to repair on top of that without sanding and getting rid of the old, deteriorating clearcoat. Sadly, you can’t just put a patch on top of it—because what you’re going to do is just cover up what’ll eventually get worse anyway.
“Once it gets to that point, you’ve got to sand it flat. You’ve got to get the old coating off of there, put a good primer on it, sand it, and prep it for paint again. There’s just no shortcut.”
2. What is Better, a Single- or Two-Stage Paint System? (Reader Submitted)
“A single-stage paint job means that the color, the gloss, and the strength are all built into one layer. That’s typically in about three coats. And the way that paint works is that it cures from the bottom up, and dries from the top down. So as this layer cures, your three coats blend together. My favorite analogy is ‘it becomes the M&Ms shell and the candy all at once.’
“Whereas a basecoat/clearcoat finish is a color coat followed by a clearcoat that still predominately stays two layers.
“A single-stage finish is sprayed all at once. You pull the trigger the first time and you’re committed to finishing the paint job. For the two-stage finish, you have a chance to stop, assess, repair, and move on at every stage.
“Logically it seems like the single-stage might be easier to shoot. But the truth is, since you can take your time and stop, a base coat/clearcoat two-stage paint job gives you more freedom to relax and see the process. Bring in an alternate light source. If you’ve got some dirt in it, you can sand it out and reapply.
“So when I’m coaching people to do their first paint job, I gently recommend a two-stage. Just because you have more control.”
3. Can You Over-Primer a Car? How Many Coats is Too Many? (Reader Submitted)
“So…(Laughs)…the answer is yes.
“People have a misconception over what the word ‘primer‘ means. It’s not one specific product, so you have to think about what primer you’re using and what purpose it’s going to fulfill.
“A lot of people use a primer sealer like an epoxy coating if they have their project sandblasted and want to protect it from rust. Well, epoxy primer is not a high-build primer. You can’t sand it, you can’t build it up again, and block-out your panels with it.
“Primer surfacer, typically a urethane, is designed for three, maybe four, coats. And it’s used primarily in collision repair for straightening out bodywork and in preparation for the application of the paint. It’s high-build, but it’s not crazy high-build.
“Now we come in with the big dog, primer filler. It’s a polyester composition, which is exactly the same thing as your wipeable body fillers are. The top custom shops use primer filler as the last stage of body work.
“So, how many coats is too many and which ones to use? Every primer at SummitRacing.com has a downloadable TDS tech sheet at the bottom of the product page (example). The TDS tech sheet tells you everything you need to know about that product, how many coats are necessary, how to prep it, sandpaper grit, gun recommendations, tip size, between coat time, everything.”
4. What Advice Do You Have to Help Folks Take the First Step to a DIY Paint Job?
“We could talk for hours on this. But here’s my advice. Yes, it’s a complicated procedure, it’s a long chain of procedure, but every link in that chain is ridiculously simple.
“The secret to paint and body is finding the correct steps in the procedure. The truth is, you have to understand that it’s quite simple when you break it down into each individual step.
“From there, you’ve got to dive into the educational aspect. The basics of the basics.
“For instance, the first thing you buy is not your spray gun. That’s the last thing you buy. The first thing is your air compressor. Make sure you’ve got the right tools in order to do the job in the first place.”
5. Is there a Common, Recurring Question or Topic from New DIY’ers?
“People have a misconception about how long it’s going to take. It’s immense, so let’s break it down a little bit.
“Let’s say we’ve got a 40 hour work week. So now we’ve only got Saturday and Sunday. It’s nine o’clock in the morning, I get out into the shop and work until about four, that’s maybe about six, seven hours. Same thing on Sunday. That’s about 12 hours of real work time on my car, a week.
“So if you consider your average paint job is going to take about 200 hours, just for a basic scuff-n-shoot—that’s going to take up a lot of weekends.
“I just tell people to be realistic with their expectations.”
6. How Should Folks Practice Spraying Before Getting to the Real Thing?
“When I teach, I use water-based craft paint, big cardboard boxes, and my favorite spray gun.
“Step one, just run some water through your spray gun, practice. Step two, get your craft paint, thin it down—practice your overlaps and gun distance. Figure out what it feels like to fail, when there’s nothing at risk.
“Step three, go to your local body shop’s junk pile and get a free panel. They throw them away. Or go to a scrapyard, they’re super cheap. Get an actual three-dimensional automotive fender or a door and prep it. Download your TDS tech sheets and get familiar with the materials so you understand how they act.
“Crawl, walk, run. Get familiar with the equipment, get used to how it sprays. You’ll really appreciate that preparedness when it comes to paint your project. Because you’re going to be ready.”
7. What PPE or Safety Equipment Do You Need for Automotive Painting?
“It’s not the 1950s anymore. As paint products have become more sophisticated, the concentration goes up. You just have to protect yourself.
“A full face mask is better but a cartridge-style mask is good, just get yourself some good safety glasses that fit your face. The best possible setup is a supplied fresh air setup but if you can’t afford it, a full-face charcoal respirator unit is the best alternative.
“But a charcoal respirator mask with safety glasses with a good seal works too—but do a sniff test. Fit your mask up to your face, get some bathroom air freshener, and spray it in a halo around your body. If you can’t smell the air freshener, you’ve got a good seal.
“Cover your eyes; the activators in these paints react to moisture.
“We have to be proactive with PPE.”
8. What Weather/Climate Concerns Should a DIY Painter Take Into Account?
“Paint products are designed to work best at 50 percent relative humidity and 72 degrees Fahrenheit with adequate air movement. That’s in every manufacturer’s instruction sheets.
“So, depending on where you are in the country, at some point during the year, you’re probably going to have perfect conditions. In Arizona, maybe its December. It’s springtime where I’m at in Tennessee. In Southern California…well, you lucky suckers…it’s all year ’round.
“Paint kind of shuts down, on the low end, below 60 degrees. Above 100 degrees? You’re not going to have any success.
“However, there is as much as a 30 degree differential between daylight and darkness. 100 degrees during the day? It might be 70 degrees at three a.m., so you coffee-up and spray your stuff at three a.m.!
“At the shop I used to work at, we had to outsmart the weather. I’d come in at three a.m., get my stuff masked up, do my spraying before 10 and my polishing before noon.
“The time of day also affects insects as well. Bugs like to sleep in. Get your spraying done before noon and you’re going to have less insect damage in your paint job too.”
9. Are Some Colors Easier to Spray Than Others?
“Metallic silvers are a challenge, golds are a challenge. That’s due to the way we see them through the lens of the clearcoat—it matters more. The dark colors seem like they’re easier to spray, but that’s because they just show us less.
A solid color that is difficult to spray, believe it or not, is white. You get snowblind. You start staring at it, and it overpowers your eyes. And you have to look away, purge your eyes, then look back at the panel. Especially when you’re into the really shiny clear layers. It can really blind you.
It’s not impossible, it just requires a bit more diligence and, more importantly, proper chemistry selection.
10. Do You Have Tips on Good Paint Chemistry Selection?
You don’t have to be a chemist to understand catalysts and reducers, we just have to understand the condition and temperature that we’re spraying in—and pick 10 degrees above that.
If it’s 70 degrees, go for 80 degree chemistry, if its 80 to 85 degrees, go for your slower (90 to 95 degree) reducers and catalysts. If it’s above 95, seriously consider spraying in the morning when it’s cooler.
If it’s below 60 degrees, same thing, reach for 70 degree chemistry.
It’s that simple. Reach for 10 degrees above your ambient air temperatures, and you’re going to be right in-line for your paint to do what it’s designed to do—which is flow out of the gun, rather than being forced out of the gun.
You can hear more from this interview in the OnAllCylinders Podcasts section.
And get more info on Kevin and his incredible Paintucation series at Paintucation.com.