How Does Your Kart Look Now?

2010

As we racing competitors get the first few races of the season behind us those big black tire marks down the side panels and deep nose cone scratches begin to grow and multiply. Though these marks are nothing more than racing evidence of wheel to wheel action they eventually become eye sores on a once shiny paint job on our precious race machines. The sole purpose of this article is to try and help those who want to learn how to repair and repaint their karts instead of paying big bucks to the local body shops. My years of working in a body shop are far gone (I hope) but occasional auto paint jobs on the side after work keep me somewhat up to date on all the new products for the professional.

I will not cover the backbone work needed to patch holes or repair with body filler in this article because personally I don’t believe it is a good idea to use fillers in nose or side panels. It becomes jagged and a real eyesore when it gets its first big smack. However using marine fiberglass cloth and resin can make a repair sometimes stronger than the original. I personally like to reinforce my nosecone from the back before the first use. You must be careful not to over do it though. A friend had a nose with steel sandwiched between layers of glass and my thoughts were that chassis or bumper damage may occur before the nose cone would give.

Our first goal will be to decide what type of refinishing materials we want to use. If you are going to use one color only, an inexpensive acrylic enamel such as DuPont Centari will be fine. Since I’m the creative type I like stripes, flames and other twisted graphics. For these multi-colored jobs basecoat/clearcoats are my choice because of the work times between colors. Most coats of base color only need about 20 minutes of dry time before tape can be applied to separate colors. Also the ease of use of basecoat systems ,the beginner novice can produce professional looking results on the first try. Another advantage to the clear jobs is the ability to correct mistakes without repainting. Surface imperfections such as runs, orange peel (roughness), and dirt/lent can usually be wet sanded with 1200 grit sandpaper and compounded the next day for a mirror like job in just a few minutes. I do not recommend doing this in the winter months when it is below 55 degrees without waiting an extra day or so. To not get to far ahead of myself I guess I better start from the prep and walk you through the process.

Step one is prepping the panels you are going to paint properly. I recommend washing the panels with soap and water and let them dry thoroughly. Next wash them with a surface cleaner designed for this specific job. Martin Senour Paints makes a good one called Kleanz Eazy, once in a while I will use DuPont’s Prep Sol. It is important that you do not use thinners or reducers on plastic or unpainted fiberglass as they will release the mold agents and cause severe adhesion problems down the road. I like to dry sand with 320 grit or 400 wet sand as a final sanding before undercoating. For deep scratches you can start with coarser papers but step down in graduations until you are done (ex. 80 grit, then 180 grit, down to 220 grit then finish with 320). Wet sanding with slight pressure works well for removing scratches. A good rule of thumb is “if you can feel the scratches you will definitely see them after painting”, I like to lay my hand flat on the panels for better feel and water will also interfere somewhat with your sense of feel. After you finish sanding you will need to clean panels with the surface prep cleaner again, this time use two clean rags and wipe the solvent on with one and quickly come behind with the other and remove the wet solvents before the panels air dry. This will ensure all wax and grease deposits are removed and will help eliminate fish eyes. Be sure to not touch the panels with your fingers when your done, it will leave oil deposits on the panels! The last step prior to painting is wiping over the panels with a tack cloth (you can purchase one where you buy the paint for about $1.00).

Before I decide on an undercoat I analyze my needs. On plastic (some fiberglass) a bonding clear is recommended for best adhesion. SEM makes a good inexpensive product. I then use a non-sanding sealer if my surface is smooth, Martin Senour’s is 5500 Poly Satin and can be used under most any topcoat. For more fill you may use a lacquer primer/filler like DuPont’s Primeez and sand it after an hour or so. Choose a color close to the topcoat if possible to help hide light scratches. My absolute favorite undercoat is MS’s Tec/Prime, this is a two part urethane primer capable of filling a cinder block if I need. It also sands very easy for excellent fill, I think DuPont’s is URO Prime. These are very expensive so don’t faint at the counter if this is the product you desire. I find that their adhesion is outstanding and are considerably more durable against harder collisions than the cheaper products.

Now that you have a ready to paint panel and have chosen your colors it’s time to apply the background color. A cheap $29.00 paint gun made in Taiwan will be sufficient for application of all materials you will utilize. Also a two horsepower compressor should be adequate. Base colors should need only about 35-40 psi at the gun. Acme, Lily, and Martin Senor all have basecoats that are mixed one part stabilizer to one part paint (sometimes ready to spray from the can). These bases dry very quickly and will be dull in color. The clear will give it the shine and usually tend to brighten the color itself from what you see after it dries. Don’t try to make them shiny by applying it on heavy.Use just enough paint to cover evenly (2 or 3 coats) Metallics need to be misted after a third coat with your gun at a distance of 14 or more inches away from the panel to eliminate streaking. If you apply a metallic color to heavy it will sag or molt. Let it dry and just mist a coat over top two or three times allowing each to dry before applying the next. The first base should be allowed to dry at least 20 minutes (read product recommendation) before you tape off stripes or graphics. I like to tape a nonconspicuous area to test adhesion and dryness before I tape a bigger area. If paint doesn’t come off when you remove the test strip your ready to proceed.

I strongly advise you to spend a couple extra dollars and buy good masking tape such as 3M. Cheaper ones like the Anchor 0.89 roll will cause you much grief. The glues tend to under or over adhere and are nearly impossible to remove if left on any amount of time. For striping use a thin striping oriented tape, also made by 3M (light green in color). These come in widths as fine as 1/16 for tight curves or 1/4 inch works well for stripes. You may then mask off larger areas with a 3M 3/4 inch width tape overlapped onto newspaper or butcher paper.

If your ready for the second color then lets go. Blends should start out from the darker area and moved to the lighter area. Rotate your wrist where the blending starts. I cut back on the fluid level to mix my colors together by making them somewhat transparent between the two. Use as light a coat as possible on the edges where the tape is for smoother transition lines between two colors. Be careful not to make them too light as you will see through them to the undercoat. A few more tips on additional colors are, first, you can start with two colors and mix them together for additional colors. This will give you colors that compliment each other well. You can also get a color wheel (probably on the web) to help choose colors that don’t clash. I also go to the distributor and buy mismatched colors that body shops leave behind for a tiny fraction of the cost of custom mixed paints. Also remember reds and yellows will be more expensive than black, white, or blues. The last pint of red I bought was $26.00, though one pint will nearly paint a dozen karts. If you are done with all the basecoats remove all tape between the colors in preparation for the clearcoat.

I highly recommend the use of Urethane clearcoats for the final stage of your paint job. Most of the manufacturers only sell these products in larger quantities. You will most likely have to buy enough to paint for months, minimum of 1 quart (don’t let if freeze and seal it tight). The initial cost is the worst and as time passes you will probably only need to buy basecoat colors as your tastes change. The Martin Senour Tec/Clear is reduced 4 parts of clear to 1 part of catylst and 1 part of reducer.I like about 60 psi at the gun for good atomization. Some clears come ready to spray with just adding reducers. Most local shops or jobbers will be glad to help choose your products. Make sure the temp. is considered when choosing reducers. On small jobs like kart painting I prefer to go one step cooler on reducer to help speed up dry times (faster drying reducer). After applying the third or fourth coat of clear wait ten minutes or so and remove all remaining masking {carefully}. Let the panels dry overnight before handling and on cooler nights be careful as your fingers may still leave imprints in the clearcoat. If you do need to wet sand and buff the clear for a better looking job make sure your sandpaper stays dirt and sand free as this may scratch the surface beyond repair.

These methods are the ones I use when I paint karts or autos for friends or myself and in no way do I consider them to be the only method available or correct. I also recommend that anyone attempting these procedures to first comply with material manufacturers recommendations as labeled and request material safety data form sheets and application literature. Safety cannot be expressed enough when using these materials but be sure to ‘USE AN APPROVED NIOSH OSHA APPROVED PAINT MASK” when applying any amount of material of any kind.

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