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The Auto Painting Tips
Newsletter
With Chris Curwen & Expert Auto Painter - Dave Gage (Car Cosmetics) July 3rd, 2007 - Issue 10 In this issue:
******************************************************************************** The process of straightening a panel involves reversing the deformation. Believe it is much more complex than simply hammering the dent out from the other side as you may have seen in the movies! Instead you must work from the outer perimeter of the damaged area towards the point of impact. This can be a little tricky if there is more than one area of impact. Only a portion of the damage to the panel will be suffered from the actual impact itself, with most of the damage coming from emanating forces. Think about this: A friend of ours is a van driver and one day he was involved in a minor road traffic accident whereby a vehicle had driven into the back of him. Upon inspecting the rear of his van he realized that no damage had been done and was happy to leave the incident at that. It wasn't until he arrived at his location however, when he tried to open the back door of his van that he realized the extent of the accident. He couldn't open the back door! Since the door was secured in place by its hinges, the impact to the door had caused a minor deformation to them causing the door to jam closed. Back to our topic... It is quite common for a dent in one portion of the panel to cause another area on the same panel to bulge outward. Start by hammering this outward bulged area back into the correct alignment before you start hammering the actual dented area back into place. If you attempt to straighten the dent first it will cause the metal in the bulged area to stretch. Aim to straighten the panel to within 1/16 of an inch of its original form. You can then use a thin layer of plastic body filler to cover up any remaining imperfections. Unless you are able to finish the panel without using any filler, the repaired area needs to be left slightly lower than the undamaged area surrounding it. This is done to keep the body filler from building up above the surrounding area. Never apply body filler at more than 1/8 inch thick at its deepest point. Doing so will result in the filler either sagging or cracking. The following is one achievable method to help you repair those dents in no time at all. * You will need to pull out the dent in the sheet metal in order to straighten it. This is made easier if you weld small metal rods to the sheet metal using a Rospot or a stud gun. The rods should measure approx 1/8 inch in diameter and 2.5 inches long. * Using a slide hammer, slip it over the rods one at a time. You can then hammer out the dent using the slide to get the sheet metal back into its original position. You may need to tap the metal back in a little if you accidentally hammer it out too far. The slide hammer is then moved over to the next rod. It does take practice to read the dents and know exactly where to apply the right amount of pressure. * Once you've done this, check your work. You need to ensure every part of the panel is as close to its original shape as possible. You also don't want the panel to be too high in any areas. Any high spots need to be hammered back into place and any low spots need to be filled. * After all the pulling is done the rods can be cut off as close to the body as possible. You can accomplish this using a pair of diagonal cutters. The remaining stubs are easy to grind down using a coarse sanding disc. * Next you will need to smooth the surface using body filler. After that, add a light coat of glazing putty for the final surface. A paint product mixing board has a tablet of disposable sheets for use when mixing filler or glaze. The filler will be mixed and spread and then that sheet would be torn off and thrown away. Don't worry about any slight high spots; they can easily be guided back into place with the use of a small hammer. You will find that older vehicles have thicker sheet metal compared with newer vehicles; which have panels that are a lot thinner and more flexible. Adjust the amount of effort you use to straighten the panel depending on the age of the vehicle. * Use a flexible spreader to apply the filler to any low spots. Be careful to prevent air bubbles from forming. After the filler hardens it can then be sanded and shaped using 80- or 100-grit sandpaper. That's it! ******************************************************************************** Questions & Answers Today Ronald Divino asks: 'I would like to know more about the different kinds of spray paint guns and how to use them correctly.' This is an important part of auto painting to understand. We talked about High Volume Low Pressure (HVLP), Spray Paint Guns, what you MUST consider when purchasing a spray paint gun, how to thoroughly clean your gun and spray gun manoeuvrability in 'Auto Painting Tips' Newsletter Issue 02 and 03. For risk of repeating ourselves Ronald, we recommend you take a look at our archive and issues 02 & 03 on Spray Paint Guns. You will find information in those issues about the types of spray paint gun, how you are to use them in relation to the surface being painted and a whole host of other topic related information. You'll also discover why purchasing an expensive, top quality HVLP spray paint gun will more than pay for itself in just a few paint jobs and therefore save you money overall. And don't forget, if you've purchased a copy of 'How to Paint a Car - The System' you'll be able to watch professional full-time car painters using top quality spray paint guns on real customers vehicles. We hope this helps Ronald. ******************************************************************************** That's all we have for you this week. Thank you very much for reading. We both hope this issue has been of valued interest to you. Next week we'll continue on the topic of Bodywork repair and talk about Replacing a Panel. Happy Painting! Chris Curwen & Dave Gage www.LearnAutoPainting.com © 2007
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