The Beginner's Guide To Body & Paint Work: Part II
Save A Huge Wad Of Cash By Doing It Yourself
By Jim Rizzo
Lucky for us hot rodders, Summit Racing Equipment, the world's largest direct mail and Internet supplier of high performance automotive parts, has introduced the Summit Racing Paint and Auto Refinishing System. The product line includes top coat paints, activators, clear coats, primers, and paint reducers--all at a significantly more affordable price than comparable brands. This is great news as it's just one more reason for us not to disregard the idea of trying our hand at paint spraying; at the least, more affordable materials will allow us to make a mistake or two and still spend less cash than we would have!
Okay, here we go again. Since I'm pretty long-winded on certain subjects, I ran out of space in the last issue, so I'm hoping to cram the rest of my paint and body ramblings into the precious space allotted to me this month. As you'll hopefully recall, in the first installment we ended by going over the different types of spray equipment common in the auto painting end of refinishing. Today we'll continue by spending a bit of time talking about spray gun operation, spraying technique, and gun and equipment maintenance.
Air Tool Maintenance
Now that we've gotten a look at the basic tools of the trade, seen their most important components, and explained how they operate, it's only logical to touch base on the techniques of using and maintaining `em. The spray equipment you've chosen, be they conventional or HVLP in design, will give you excellent results if used and maintained properly. Now, as you're all well aware, we can talk about how to use and take care of your tools `til we're blue in the face. But there's nothing like hands-on experience to get these things to stick in your mind. So grab a couple of the more frequently used air tools you've added to your arsenal (the DA sander, the long board sander, and the 5-inch grinder) and keep `em handy as we go along.
The first air tools to see duty in the body working process are more often than not the grinder and the dual-action sander. Most operations require that the existing finish be removed from the vehicle surface before continuing on with the repair. Sometimes it's a couple of layers of paint and primer, and sometimes there may be a layer of filler to contend with as well. The grinder and DA are actually quite simple tools. They're basically air-powered motors with handgrips and right-angle shafts to which a backing pad and disc are attached. A trigger actuates a valve, allowing compressed air to flow through the tool. When it's depressed, the compressed air passes through a passageway to a chamber which houses what can be best described as a miniature turbine. The turbine (or motor) is a machined disc that has a number of slots milled into its outer edge. Small vanes or blades usually made of a rigid, fibrous material are fit into these slots to form a sort of paddle wheel, or what looks like the type of blade you'd see in a jet engine.
The compressed air flows through the inlet of the DA, or grinder's air passage, into one side of the chamber that houses this turbine-type blade and, in order to escape, has to flow past the blades. The pressure and volume of air passing through the chamber spins the blade which, in turn, spins the shaft holding the backing pad and grinding or sanding disc. As with anything that spins at high rpm, proper lubrication is a must. As you're aware, bearings or bushings that surround a spinning shaft won't last too long if soiled by contaminants or with little or no lubrication.
The same holds true with your long-board sander. The long-board is primarily used for sanding large flat expanses of body filler and it operates a bit differently than the other sanders. It uses an air-actuated piston (or pistons) to achieve its back-and-forth movement, and though it doesn't use a spinning, blade-type motor, it requires regular lubrication, even more than circular type sanders.
Solid particle contaminants shouldn't be a major problem if you've properly configured your air supply (like we talked about last month). But the massive amounts of hot, moist, compressed air that pass through these tools and the extremely high rpm at which they spin will. To combat the inherent wear and to ensure continued performance of these tools, lubrication of some type is a must. To make sure they stay in tip-top condition and are always ready to use, you've gotta keep `em oiled!
For those of us who know that we'll more often than not forget to lube our tools daily, there are many types of automatic oilers on the market today. These are designed to inject the correct amount of oil into the tool as you work, saving you from having to remember to do it on your own. You can choose between small tool-mounted units or larger capacity ones that can be permanently attached to the garage air supply system. If you choose the permanent air supply oiler assembly, it's important that you make sure it's on a line that's dedicated to your air tools only! You don't want to connect your spray gun to a line that's connected to a permanent oiler!
There are many brands of air tool oil on the market (available at any body supply or tool store), or you can use products like 3-in-1 or Marvel Mystery Oil. Whatever you choose to use, make sure it's a very thin, light lubricant and that you keep all your air-powered sanders and grinders oiled daily!
When it comes to your sanding equipment, there's another thing to remember. Whenever you set down any of your air-powered sanders, always place it so the sanding pad is on its face! Never lay a DA, grinder, or air-board on its side. The weight of a tool laying on the edge of its pad will cause a flat spot or deformation in the pad. If you've got a sanding pad that has a deformed edge, that edge will (depending in the angle of depression) either take more or less material off than the balance of the pad face. This will in turn cause the surface being sanded to become uneven.
Spray Gun Setup And Technique
Okay, before we get into the really hands-on part of my rambling, this might be a good time to refer to the cover blurb from last month's issue regarding painting a car for around $300. Since you're gonna need paint and material for both your practice sessions and what we're hoping is your first successful paint job, I just have to take the time to clue you in to what I think is some pretty exciting news. It's exciting because in this day and age saving a big chunk of cold hard cash is paramount, and recently Summit Racing Equipment has introduced a line of high-quality and extremely affordable urethane paint, catalysts, reducers, and associated primers, sealers, and solvents.
Recently Candy and I purchased the paint and materials for her Hot Rod Girl Total Performance '27 T from Summit and were floored by the savings over equivalent materials from the local paint and body jobber. Take a second and look at the following comparison, keeping in mind that the Summit Racing Paint and Refinishing System products are every bit as good, or even better in performance and quality than what I normally use (a big-name brand that I hesitate to name for fear of pissin' somebody off).
