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Autobody Refinishing and Painting - Autobody 101Taking The Mystery Out Of Automotive Refinishing From the April, 2011 issue of Modified Mustangs & Fords By Kevin Tetz Photography by Jim Smart, Kevin Tetz, The Eastwood Company
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The process of painting a car has been a series of constant improvements and innovations since the 1920s. Although the basic mechanics of spray-painting are essentially the same, the technology and equipment has changed drastically since the first automotive assembly lines began production. The fact that about every four years or so the entire paint industry is set on its ear and changed due to constant EPA pressure makes it a little intimidating for someone who's never "done it themselves," however, it's not all that complicated, and the basic techniques of applying paint have not changed that much. Like the concrete slab your... Like the concrete slab your house sits on, the sheetmetal is the foundation for your paintjob, and it needs to be as straight as possible. Metalworking takes practice. Metal masters like Ron Covell have studied for decades to perfect their skills, and their craftsmanship shows their tenure. Understanding metal and how it reacts is important, and you can get a good grasp of basic action/reaction techniques and metal forming with some simple tools. You can usually go by any autobody shop in the country and get "take off" panels that are damaged, and then practice hammer-and-dolly techniques until your hands hurt. This will give you a good idea of how sheetmetal reacts, and what's required to repair and reshape it. We're not going to say that autobody work is easy, it's not! Like anything else, it's a skill that takes repetition and time to perfect. The good news is that the fundamentals are quite simple and easy to understand when broken down into basic steps. Those simple steps, when strung together into a procedure, are what create award-winning show cars. Can you get show-winning paint the first time out? Yes, but it's not typical. We've seen it done several times, but it takes a lot of dedication on the part of the student. Although it's unusual to win "best paint" on your first paintjob, what is typical is that when you follow some simple guidelines and pay attention to the fundamentals, your first results are usually pretty darn good. A successful paint and body job typically prompts a buddy into asking who painted the car, followed by, "What would you charge to do mine?" And a technician, small business, or solid weekend "paint and body" warrior is born! If you have the urge to learn the necessary skills to do it yourself, or to do most of the work and turn it over to somebody to shoot the paint, or if you just want to know what questions to ask so you don't get taken to the cleaners when you're looking for a qualified shop, this article should get you up to speed. Start with your local car clubs and ask a bazillion questions! Painting your own car can be an incredibly rewarding experience, and one that will empower you, save you money, and possibly put a little scratch in your pocket when your buddies find out you did it yourself! Even if you don't plan on doing the painting, or even any of the bodywork yourself, you need to educate yourself to know what to ask for. Don't set yourself up for disappointment by letting your project sit in the back corner of a shop that doesn't care. Here are five things to look for in a good, quality autobody or restoration shop: 1. Clean, clean, clean: If the shop doesn't care about its shop or tools, it doesn't care about your car...move on! 2. Check references: If a shop manager won't give you references to call, he's got something to hide. Period. Move on. 3. You get what you pay for: Shop around for the best value, not the best price. Less expensive is OK, cheap is lousy, and you'll regret it long after the discount is gone. 4. Turn-around time: Nobody can predict unforeseen work that needs to be done, so don't expect a timetable to be written in stone. Asking for a reasonable estimate on how long it will take is perfectly acceptable though. 5. Insurance: Ask if the shop has insurance on your car while it's in the shop's care. If it doesn't, move on. Always keep insurance on any project for your own personal protection, but don't let them lean on your premiums. A legitimate shop will have a garage keeper's policy in place.  A spot weld cutter is pretty...  A spot weld cutter is pretty important to have when removing sheetmetal. They're affordable and come in several styles. My favorite is the one with the replaceable blades. This way you can change blades and cutter sizes depending on what you're working on, or when the cutting edge gets dull.  Now, it's more affordable...  Now, it's more affordable than ever to pick up a good wire-feed MIG welder, which is the most common choice for replacing or repairing sheetmetal. The big names have affordable options, but specialty companies like Eastwood and Summit Racing have their own branded lines of MIG welders for a bargain price.  Resist the urge to go with...  Resist the urge to go with "flux core" welding wire, and get a separate shielding gas setup. Shielding gas (usually argon/CO2 in a 75/25-percent ratio, respectively) is blown onto the weld-pool and chases out oxygen and impurities, giving the molten work piece the best possible chance to fuse to another piece of metal. Don't skimp on safety, either. Notice the gloves and welding helmet.  Consumables like sandpaper,...  Consumables like sandpaper, grinding discs, and masking supplies can be picked up at any autobody "jobber" store. Norton has an affordable, high-quality line of products that covers all the bases well.  Most bodymen use air tools....  Most bodymen use air tools. For the hobby guy, there's nothing wrong with the less expensive brands, but don't expect as long a life from them as name-brand tools. More important (critical, actually) is a good compressor with at least a 5hp pump, and a 60-gallon tank. Look for at least 11 SCFM (air volume output) to be sure your compressor doesn't run all the time, which causes moisture to build up in the tank and lines. Said moisture will contaminate your tools, project, and break your heart when the dreaded "fisheyes' show up in your final paintjob.  You can get by without air...  You can get by without air sanders, but they make your life easier, and have a flat "foot" that contacts your work piece. You can't create a flat panel with a curved surface-i.e. your hands and fingertips-so use sanding blocks and boards for shaping your filler, and blocking primer-surfacer. There are plenty of options, but these "soft sanders" are excellent, and inexpensive to boot.  A "D/A" (dual-action sander)...  A "D/A" (dual-action sander) oscillates as it rotates, making a smooth and controlled cut. Prices range from $30 to $300, and the price usually reflects the quality.  An inline sander or air file...  An inline sander or air file is a handy tool for blocking filler on large flat panels. They're all air hogs, so again, match the cfm draw of your tools with the output of your compressor.  A small angle grinder works...  A small angle grinder works wonders for grinding welds, or getting into tight areas. These are inexpensive, and with a twist-loc attachment, become very versatile with quick change capability.  With the metal as straight...  With the metal as straight as possible, polyester filler (more commonly known as Bondo) is the next step. If you like Chip Foose, Charlie Hutton, Bobby Alloway, George Barris, Tim Strange, or Troy Trepanier's quality of work, then "Bondo" is going to be on your car. It's not a crime or a sin, it just needs to be used properly. The goal is to have it thin-no more than 1/4-inch, if possible. Filler needs aggressive scratches to hold on to-36- or 40-grit is standard. It's likely that 80 percent of your filler will end up in a pile of dust on the floor, but don't skimp on quality. The better quality fillers work down easier and have a minimal amount of shrinkage-nobody wants shrinkage.  Once the rough shape is established,...  Once the rough shape is established, there are usually pinholes and deep scratches from the aggressive (36-grit) sandpaper and blocking. The next step is to move up to 80-grit, followed by finishing putty. This is catalyzed with the same peroxide hardener as the first stage, but has much finer talc and more resin, making it flow out and fill in minor pinholes and imperfections. This filler gets blocked with 80- or 180-grit sandpaper, and sets up the repair to be primed, as a final stage of the bodywork.  Paint, primer, primer surfacer,...  Paint, primer, primer surfacer, and primer sealer are all applied wet, primarily so they can self-level as they dry, but more importantly to be transferred to the panel or car in liquid form, via the aforementioned spray equipment. Solvents are the main cause of problems in paint, but the most necessary component of the process. Think of solvents as a "vehicle," just like a car gets you to work; the solvent allows the paint to get to the panel.  A paint gun is a lot like...  A paint gun is a lot like a carburetor in that air is forced into a stream of liquid, and with the help of forced air jets directed at different angles into the stream, the liquid is broken up into smaller particles (atomized). Prices range from $50 to $700 depending on name brand and quality. For a good, all-around spray gun with low air demands, Eastwood's Concourse gun fits the bill.  The days of the "primer gun"...  The days of the "primer gun" hanging on a hook in the middle of the room filled with lacquer primer are long gone. Primer plays a critical role as an undercoat, and different primers have different roles. You can plainly see the difference between a topcoat gun...  ... and a primer gun, and...  ... and a primer gun, and how each is designed for a specific purpose.  A primer/sealer (usually epoxy),...  A primer/sealer (usually epoxy), is applied to bare, properly prepped steel, and is used as a "tie-coating" giving either fillers or primer/surfacers a compatible surface to sit on. Most primer/sealers are not sandable, and are not designed to build up or fill imperfections-don't get the two confused.  Primer/surfacer-a high-build...  Primer/surfacer-a high-build primer with talc and body built in-is designed to be sanded and leveled to make a flat surface for the paint to sit on. Polyester primer shrinks very little, and is usually sprayed directly over bodywork for the purpose of aggressive blocking and straightening. 2K or urethane primer/surfacer is much easier to sand, but can't be layered up like poly-primers due to the higher solvent content, and the possibility of shrink-back, which will show sand scratches through the topcoats. A few coats of 2K surfacer are the perfect foundation for your paintjob, but resist the urge to use multiple coats-it'll bite you in the long run.  There are plenty of excellent,...  There are plenty of excellent, low-cost alternatives when it comes to paint. Automotive paint was lacquer and enamel in the early days, and some purists, restoration shops, and furniture makers still use those old technologies although the older systems are extremely difficult to find. Urethane, either acrylic urethane or polyurethane, has replaced the older systems, and is much improved in both appearance and durability. Today's standard is a two-stage system, or basecoat/clearcoat, and is exactly what it sounds like. The color is laid down first, followed by a clearcoat, which gives the paint its gloss and strength.  There are different variations...  There are different variations of this theme, with three- and four-stage specialty coatings, but the concept is the same. One of the paints from decades ago that's still in use is Imron, which is a Dupont brand name. Imron is extremely strong, and very toxic to use. It's commonly used on fleet vehicles and transport trucks, and holds up well on aircraft and race cars as well. However, it's expensive and not practical for a weekend warrior. Base/clear systems are much better suited to a hobbyist.  Using any paint system with...  Using any paint system with a hardener in it requires the use of a fresh air supply, and there are hobby units like this one that are budget friendly.  Whether it's a home-made booth...  Whether it's a home-made booth or a rented booth like this one, use a facility that can contain the toxic chemicals and filter the overspray, and protect your paintjob from airborne dirt, bugs, lint, and other contamination.  If you're setting up your...  If you're setting up your own homemade booth, use the proper type of air line-not PVC! PVC deteriorates under UV exposure and can explode under pressure. A line kit, like this one from Eastwood, gives you everything you need to plumb your home shop.  Remember to place your water...  Remember to place your water traps and filters at least 20 feet away from the compressor, otherwise you're letting the condensed moisture travel past the filter without giving it a chance to separate, where it can then be filtered and removed from your system.  How hard can it be? Painting...  How hard can it be? Painting your own car is a challenge, but with some study and practice it's a very rewarding part of the hobby. Learning guides like Paintucation DVDs show a literal example of procedures and projects. Instructional DVDs and online forums such as Autobody101.com are an excellent place to learn techniques and ask questions.
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