I’ve known several people who painted their cheapo transportation with a brush or a roller. Perhaps you’ve parked next to that ’65 VW Micro Bus whose owners painted a colorful rainbow down the side?
I lived next door to those people in 1969.
But if that was your last experience with a brush, roller and car paint, heads up. Welcome to the new century – where, just like the last century, labor time is the most expensive thing in the body shop and any process or tool that saves labor time will pay for itself quickly.
Non-sprayed primers have that potential.
At a real-world door rate of $42 per hour, every minute of every techs labor time is worth 70 cents. Even if it takes him as little as 10 minutes to mask a panel against overspray, that’s $7 per primer application in just masking labor. Then add in the labor time to clean the spray gun – five minutes at 70 cents is $3.50 – and another 50 cents in solvent cost. Add the cost of the masking tape, masking paper and plastic sheeting – say $1 average on small areas – and you’d see a savings on each repair of about $12 when you don’t mask.
The average paint shop in the country sprays two or three cars every day. So even if you only use the roll-on, brush-on primer on one car per day, you’d save roughly $3,000 in one year ($12 per car times 244 days).
Sound like B.S.? What if I’m only half right, and your shop is ahead just $1,500 next year?
Think about masking a rolling door, with no glass in it. Sound like two hours masking to you? Rather skip that? Me too.
Then why aren’t a majority of shops using this roll-on stuff?
Perhaps they just couldn’t believe it was possible. After all, the brush-painted cars they’d seen didn’t really look that good. We’re an industry where the last time we officially brushed paint on cars was 85 years ago – before Dr. DeVilbiss invented the atomizer (which later became a compressed-air spray gun). Most shops never tried these products because they knew they wouldn’t work.
At the other end of the spectrum, early-adopter shops were ready to throw out the primer gun, masking machines and one painter when they first heard about roll-on primers. And these products do save time, but they also take practice. It’s really tricky to roll out a repair in the center of a hood, roof or decklid and not see high spots or streaks.
Try using a roll-on primer on some areas below the mirrors first; any less critical repaired area will work. Practice makes perfect in applying these products smoothly. But pretty soon, you’ll be rollin’ out primer on everything but the biggest hoods.
A Few More Benefits …
High solids are another advantage of roll-on primers; one manufacturer estimates that you’ll use 40 percent less material when there’s no overspray. Since you don’t have to atomize the resin, it can contain higher solids – so this application method approaches 100 percent transfer efficiency. Use less labor, use less product, get build in fewer coats. Hmm … this could work.
Paint shop air quality is also improved when cars are primed without spraying. Roll-on, brush-on primer eliminates the fumes, particles and overspray that 2K primers create when they’re sprayed in the open shop – especially when the primer’s catalyzing component is an isocyanate.
In many shops, the bodyman is responsible to put the car in primer; non-spray application makes this both faster and safer when working outside the spraybooth or prep station. (All manufacturers I spoke with still recommend wearing a properly fitted, fresh charcoal respirator when applying any solvent-based resin.)
Before You Start …
Not all roll-on primers are capable of going direct-to-metal (DTM). If your brand isn’t DTM, be sure to treat the bare metal first. It’s always a good idea to bring the metal to room temperature in either case.
While the roll-on concept may be similar from brand to brand (save labor time in masking and cleaning), the actual products are executed differently. Make sure you follow the directions for the brand you’re using, not the brand you used last time. It’s also worth noting that some brands offer an iso-free product. (Even isocyanate catalyzed primers are safer when there’s no atomized cloud of overspray.)
Choosing Your Roller
Roll on the primer using the correct roller from your auto paint company, not the home improvement store. Everyone I spoke with in writing this article suggested their lower nap, least-textured roller cover. Several brands offer a couple of sizes (typically 2 to 4 inches) wide, and some have different handle lengths.
While some brands of roller cover may be cleaned and reused, remember the 70-cents-per-minute labor rule. Toss out the dirty roller cover on each car, and start fresh on the next one.
One tip that will save time during clean up is to line the roller pan with tin foil. Pull the dirty foil from the pan, use the foil to pull the cover from the roller, let them dry hard on the paint bench overnight and throw out in the ordinary trash tomorrow. Pretty slick.
Will you be able to roll out the primer smoothly enough to sand quickly? Will you be able to prime a patch without leaving hard, straight lines around the edge of the repair?
Probably, if you can paint your living room with a roller and latex wall paint without any roller marks. But if you’re so ham-handed that your living room wall looks like a textured ceiling full of high spot streaks, keep spraying primer.
There are several techniques to using each brand successfully. Why not get some input from your jobber salesperson or your paint company rep about their specific suggestions? Good salespeople can save you significant labor time by sharing what they’ve seen other successful shops do. Listen up. Non-spray primer is one of those things successful shops are using.
Get a little instruction from the salespeople, spot prime something for outside storage, roll out a couple of door jambs and see if you don’t save lots of labor time in masking and clean up. And watch your application skill level jump like a rocket.
In general, start rolling in the middle of the repair and lighten your touch toward the edge. Work in a starburst pattern from the center to the edges, crossing the star at intersecting angles to prevent hard lines from the roller’s edges.
Since you’ll have to feather the edge where the primer ends, keeping the edge thin is key. With a little practice and a nice French wrist twist at the end of the roller pass, you can featheredge the primer very well.
Keep the roller passes to the minimum; roll up and back once, not three or four times. You may actually be removing material if you keep rolling in the same area. Soft touch is the trick to application. Fully saturate the roller cover with primer so that the roller doesn’t hop and skip on the first pass.
Use the edge of the roller or a squeegee to force the primer into any pinholes you spot while applying. This is an area that roll-on, brush-on primer may do better than sprayed-on primers since surface tension of an atomized film may keep the sprayed primer from flowing to the bottom of a pinhole in the body filler. Forcing it in as you roll ensures no problems later on. Another distinct advantage to this type of primer application is the quick coverage on the inside edges of stake holes in pickup boxes or any recessed edges that must be primed.
Two to three coats of primer are typical, and most brands require mandatory flash times between coats. Because the product is applied with such high-solids levels, it’s easy to trap solvent inside the film if you pile on the subsequent coats too soon. Rather than wait fruitlessly the appointed 15 minutes (at 70 cents per minute, that’s $10.50 in labor time!) between coats, use your infrared heat light. Raising the temperature of the primer will drive the solvents into the air much faster and crosslink the catalyst quicker. Turn 45 minutes of flash time into 15 with your I/R light.
No I/R light? Then wait the full flash time between each coat. If you don’t, you may begin to remove the first coat when you roll over it with the second.
Roll-on primers have a tough job description. The product has to have enough solvent that it stays wet long enough to flow out smoothly. However, they can’t contain so much or so slow a solvent that it’s trapped inside thick coats of primer. This will either cause the primer to shrink or the color to dieback when the solvent finally does escape. It’s a careful blend that requires flash time between coats. Don’t cheat the flash time, and you’ll be pleased with the results.
When sanding non-sprayed primers, the extra care you took to brush out the edge smoothly and feather the roller lines out carefully is well-spent. Spend a few extra minutes with the French twist and save time sanding.
Since roll-on, brush-on primers will still have some texture in them no matter how skillful you get applying them, I suggest you start out with a dual-action random orbit sander (D/A). Since all roll-on primers will have some chemical trickery in the resin, they’re likely to have a harder top surface.
Quickly sand through the top coat of resin to reach the talc in the primer surfacer. If you must finish sanding by hand, either wet or dry, the underlying primer is good to go and will quickly block down.
I’m a fanatic about machine sanding versus hand sanding. It’s that 70-cents-per-minute labor thing again. Since most hand sanding is final block sanding and not shaving a mound of body filler down with 36 grit on an idiot stick, buy a super-smooth-running power block sander and save time. For you purists who must hand sand something, do the first 75 percent of sanding with the power tool and the styling lines and last 25 percent by hand.
Stop hand sanding, he says, again and again and again.
One study suggests that painters spend one-third of their hours every day sanding something. Wouldn’t you get more done if you could do the majority of sanding with a machine?
Several brush-on and squeegee-on primers also are available.
Squeegee-on products are typically catalyzed with a very fast catalyst (little working time) and resemble thinner versions of catalyzed spot putty. Small repair areas (less than 10 inches by 10 inches) are best suited for this style of non-spray application. Typically nicks and scratches are quickly primed with a squeegee.
Brush-on application works well on irregular parts like door hinges or small crevices where the roller won’t fit. No one I interviewed spoke to me about brushing primer on large areas. Rollers work much better on a larger, flat repair area. But a foam brush will reach deep into an area that would be hard to mask and spray or hard to roll across. Just remember to observe even more flash time between coats if you dab on an uneven mil build of primer with the brush.
Technique Is Key
Technique makes the biggest difference in how well these primers perform. Practice makes perfect, and any painter’s ability to roll out the edges tapered and smooth gets better the more he does it.
Labor savings is clearly the biggest advantage. Not masking against overspray saves huge amounts of labor time. And the more cars you can prime with a roller, the more time you save in masking. Additional savings accrue in clean-up time. Not flushing out the spray gun every time you need a bare spot primed saves both labor time and clean-up solvent. And cleaning up the roller and pan is a snap if you line the pan with tin foil and use a new roller cover each time.
Even if your shop uses the roll-on products only in special circumstances where masking and overspray are extremely difficult, you’ll still save money on those jobs.
Remember, every minute of labor, for every tech, is worth 70 cents at $42 per hour. Make sure your shop puts all those minutes to good use.
Writer Mark Clark, owner of Professional PBE Systems in Waterloo, Iowa, is a well-known industry speaker and consultant. He’s been a contributing editor to BodyShop Business since 1988.