Several times throughout my career, I’ve found myself sitting in a paint manufacturer’s training center. It’s usually a nice three-day break from the shop, and I pick up some useful tips. At the beginning of all these classes, the instructor always asks if we’re having any problems. I usually hear the same old complaints about lifting, dieback, fisheyes and solvent pop. Then the instructor gets to me, and I mention the difficulty I’m having controlling some of the metallic colors I have to spray.
The teacher nods knowingly and asks if anybody else is having the same problems. Ten times out of 10, nobody else owns up to any difficulties – as if an admission of having trouble means they don’t know what they’re doing.
Of course, once we get out in the training facility’s paint booth and start spraying Ford color code CX, it becomes readily apparent that metallic control is a problem faced by just about everyone.
Blending metallic colors offers a whole new set of challenges to the increasingly frustrated painter. Now we’re faced with controlling the way the flakes lie down while, at the same time, trying to deal with a nasty halo that we just can’t seem to get rid of.
As the years go by, most painters come up with what works best for them when spraying metallics to get the job done without total embarrassment. Some painters hone their spray technique to near perfection for the results they’re after. Others attempt to utilize one of many “drop-coat” techniques in use throughout the industry. A shameful majority (nobody reading this, of course) utilize the “good enough” technique, which is the quickest solution. It also renders surprisingly good results, since most customers will rarely complain about the blotchiness on their silver car’s hood.
But “good enough” isn’t good enough. We’re professionals. As such, we need to take a more professional approach to our craft. It’s never OK to return a flawed job to the customer. That being said, let’s get started on our quest to achieve metallic control.
It’s easy for painters in today’s collision shops to find themselves rushing cars in and out of the booth. It’s understandable. With many shops refusing to schedule a steady workflow, we’re often confronted with days where we have more cars to paint than we should. Combine that with the lowball paint times we receive and the newly discovered blend within deduction, and we get put in a difficult position. The only thing on our mind is getting the cars out the door.
Unfortunately, a painter who takes pride in his work just has to slow down if he’s interested in putting down the best paint job possible. If you rush a complicated metallic paint job, you’ll likely find yourself disappointed with the results, not to mention the assembly technician rolling his eyes at you behind your back. Try to remember that this is somebody’s personal property you’re painting and they’ve put their trust in you to take care of it. Slow down a bit and concentrate on what you’re doing. You just might find that those mottle-free charcoal paint jobs are more attainable than you originally thought.
The first step to painting any
paint job is a clean gun that’s operating properly. If you’ve got a sloppy pattern coming out of your gun, you’re setting yourself up for failure. Take an extra minute and spray a test pattern out on the wall (but make sure you put up a piece of masking paper first).
And don’t overlook air pressure, like so many of us have. It’s not uncommon to see a painter with the air pressure jacked up, moving his paint gun back and forth like he’s trying to put out a fire. Make sure you’re spraying at the right pressure for your gun.
Get that tech rep of yours who you haven’t seen in six months out to the shop to set up your guns with an air cap gauge. That’s really the only way to know if you’re in spec. For years, I was spraying at the wrong pressure for my basecoat gun. I had my clearcoat gun checked and was accurate with that. I knew what pressure at the wall I was supposed to be spraying at, and I mistakenly assumed that the pressure drop from the wall would be the same for all my guns. As a result, I was spraying 10 pounds below where I should have been for my higher air-consuming basecoat gun. Since I’ve gotten that straightened out, my life is a lot easier.
Don’t just assume you’re at the right pressure, folks. And stop adjusting the air pressure by ear.
Application Techniques Matter
Sloppy spray technique definitely isn’t going to help you in your quest for metallic control. Some technicians spray close and fast. Others spray slow and further away. Both can be acceptable methods of spraying provided that you have all your bases covered in the other aspects of application.
Most professional painters, by and large, know what they’re doing. I would say it’s the consistency that’s most important. Make sure your gun is pointed straight at the surface of the car. Keep your gun speed consistent and make sure you’re properly wetting up the surface.
A lot of people will (incorrectly) put the paint on dry for difficult metallic colors, thinking that the wetter they apply it, the more risk they have of mottling. But they’re shooting themselves in the foot with this thought process. I like to lean more toward the wet end of the application spectrum. Don’t get me wrong, I’m not pounding on basecoat like I do clear. I feel you have to give the flakes a chance to orient themselves, and they have no way to do this if the paint dries the second it touches the surface. Think medium wet and you should be fine.
Pattern overlap is perhaps the most important part of your application. Standard issue overlap is generally 50%. I’m going to go against conventional thinking here and promote more of a 75% overlap. I believe this gives me a more consistent chance of not screwing up in the middle of a hood and getting a tiger stripe.
My point is this: If you find yourself from time to time having difficulties painting that pale blue metallic Chevy, make sure you’ve got your basics covered in regard to application technique so you know you’re not making your life harder than it needs to be.
On practically every job, we have to utilize some blending skill. Sometimes it’s a cinch. Sometimes it’s not. Surface prep is especially important when blending out a tricky color. Not too long ago, my standard prep for a blend panel was a scuff pad and some sanding paste. This is perfectly acceptable, but it creates some issues that the painter needs to look out for, such as “metallic tracking.” You’ve got your color all blended out, and it looks nice – until you clear it and it all goes to poo. Now you see little streaks running away from the repair. That’s the metal flakes sitting in the scratches from the scuff pad and paste.
I’ve adopted the view that using good ol’ fashioned sandpaper rather than the scuff pad is the way to go. Logic tells me that it really shouldn’t make a difference, yet it does.
Most paint systems offer some type of clear basecoat to use as a wet bed prior to blending out your color. Take advantage of this product. It makes the job easier and nicer. It also helps with judging how your blend looks, and it almost eliminates any problems with metallic tracking. Most importantly, if the boss looks in the booth while you’re painting, it looks like you’re spraying on an unsanded panel, which will give him some heartburn.
Blending out your metallic color on a hood is a much more difficult task. I’m not sure if this is a mental thing, but it’s good to have a plan of attack when you’re faced with a spot repair on a silver hood. I like to utilize any body lines that may be there to help me. It’s easier and more consistent to just paint the whole darn hood and blend into the fenders, but good luck getting paid for those operations.
Sometimes I’m faced with a bear of a color on a car where I have to spot repair the hood and there are no body lines to hide a blend edge. I’m not ashamed to admit that this is a very difficult repair for me. As the paint professional, you’re the expert and know what’s best for the customer’s car. In this instance, it’s important to communicate this difficult situation to the shop manager. The best repair in these circumstances is to paint the entire hood and blend your color into the fenders. This procedure will eliminate the likely risk of a nasty halo across the hood.
Plan on Drop Coats
From time to time, we all face off with those colors that are just plain impossible to spray. Your technique is tight and you’ve got all the bases covered as far as prep and application go, but you know darn well that this color’s going to be a blotchy one. My opinion: Plan to utilize the infamous drop coat from the beginning.
I used to put coat after coat on, trying to get it right to no avail, saving the drop coat for the last possible moment after I’d admitted failure. Of course by that time, I’d run out of paint and needed to make more. So instead of wasting my time putting five extra, useless coats on, making more paint and putting on a drop coat, now I just proceed directly to the drop coat. I plan on the drop coat from the beginning.
Painters use a couple different methods as a drop coat and, with practice, the end results are very similar. One method is to over-reduce the base with either a slower reducer or with a clear basecoat. The air pressure then needs to be slightly lowered to compensate for the over-reduction. When using this technique, I find that a full trigger pull is a little too much and, instead, opt for a half trigger pull. This really slows down your gun speed and puts on the material pretty wet. It enables you to really finesse the metallics. This method works particularly well on a difficult blend but takes quite an amount of skill on a flat surface. It can sometimes be a fine line between fixing your problem and making it worse.
I belong to the school of thought that when you add an additional product to what you’re spraying, be it extra reducer or a clear basecoat, you run the risk of changing the color you’re spraying. It doesn’t happen all the time, but I’ve run into a few occasions where this will dramatically change the color’s appearance (possibly from my poor application of this technique).
Nonetheless, I avoid adding things to my basecoat. Instead, I spray my drop coat straight up.
I’ll dial back my air pressure five or so pounds and then increase my spraying distance 3 to 4 inches. Due to increased gun distance, I then compensate by considerably slowing down my gun travel. It’s important to note that I’m not putting on the basecoat dry because, once again, the flakes need to be able to orient themselves. I really concentrate on a good overlap here. I think it’s important to spray this type of drop coat immediately after your last coat, the coat in which you achieved coverage. This is sort of like an insurance policy for me in case I extend my distance a little too far from the panel. I want to eliminate the risk of putting on a dry coat.
With these two drop coat techniques, I’ve been very successful at defeating most of the problem colors I’ve come across. Give them a try, or feel free to use whatever technique you already use. Just keep in mind that dry is bad.
Good Enough Doesn’t Cut It
The final way painters deal with difficult metallic colors is to let good enough be. They claim it’s industry standard, and reassure themselves how unlikely it is that anyone will point it out. Managers are also likely to overlook slight mottling issues. They typically have their minds set on delivery dates and cycle times and are willing to take the risk of a disgruntled customer in exchange for good numbers and high volume. Not to mention the additional costs associated with a redo.
I think it’s about time all of us refinish technicians stopped viewing jobs this way and started taking a more professional approach. It should never become acceptable to let a flawed job roll out the door. As painters, we can do our part by taking our duties seriously and committing ourselves to doing the best job we possibly can.
Believe me, I understand as much as the next painter that metallic paint jobs can be really frustrating and stretch our skills to the limit. But if we slow down a little bit and think about what we’re doing, if we perform our craft in a methodical way with the end goal being a beautiful, durable finish, and if we plan ahead for any problems that may arise in each paint job, those redos will be few and far between.
If we do all that, the next time that silver BMW rolls out of the booth, all you’ll have to worry about is how to handle all the compliments you’ll be getting from the body techs.
Writer Nathan Tarr has been working in and around the collision repair industry for the last 12 years and admits to being “thoroughly addicted to auto body work. It’s my hobby as well as my job.” Sikkens certified and PPG certified, Tarr has been working as a painter for the past five years. Tarr is also a member of the Coalition for Collision Repair Excellence (CCRE) because “it was one of the only ways I could find for a technician to help make a difference.” He has been married for nine years to his lovely wife Wency – “I’ve had my eye on her ever since she moved up the street from me in the seventh grade.” They have a 2-year-old son, Hank, who likes to hunt for worms in the backyard and hide the remote control. Tarr can be reached at [email protected]yahoo.com.