September '18

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SEPTEMBER 2018 THE SHOP 61 disadvantage is that it's nearly impossible to leave that bottom layer untouched. Most of the time, that drill goes through both panels. This method can also become frustrating if the drill bits wear down quickly. Still, if this is the way you want or need to do it, start by creating a divot in the center of the spot weld using a center punch. Next, drill a 1/8-inch hole through the first layer of metal. (It takes practice to not go into the second layer.) Then, a drill bit that is the same size as the spot weld is used, usually 5/16- inch. Line the larger drill bit up with the 1/8-inch hole and drill through until the bottom layer is reached. Some folks will take a 5/16-inch bit and grind the end of it almost flat. The flat tip will help keep you from going past the bottom of the 1/8-inch guide hole. SEPARATING THE LAYERS For all of these methods, it helps to finish separating the layers using a Seam Buster or chisel. The Seam Buster is a flat, narrow chisel made of super-hardened alloy steel. It's sharpened on two edges for penetration between the two panels, allowing them to be separated with no damage. These are much more efficient than a chisel and are very durable, absorbing a lot of abuse. One Seam Buster will last through many restoration projects and show little wear. A right-angle Seam Buster is also avail- able for getting into those hard-to-reach or bonded panels. I know one technician who uses her right-angle Seam Buster to hold down metal as she's welding in patches and panels. JOANN BORTLES is an award- winning custom painter, air- brush artist, welder/fabricator, tech writer and photojournalist with over 30 years of experi- e n c e i n t h e a u t o m o t i v e industry. She is the author of seven books on automotive, motorcycle and custom painting. Her work has been featured in numerous automotive and motorcycle publications, NBC News, The Today Show, MuscleCar TV and Motor City Masters. JoAnn owns Crazy Horse Custom Paint. Here's the average result of the spot welds eliminated with the cutter with both layers in place. The separation between the layers is easy to see in the right hole. Sometimes the cutter worked exactly as promised. Other times it went through the bottom layer. This was the slowest of the three methods, as we had to keep stopping to check the depth of the cut. But, with practice it would go quicker. It also had the most impact on the bottom layer. The Steck Seam Buster is one of my favorite tools. After the spot weld is removed, use the Seam Buster to finish separating the two layers.

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