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How New Aluminum Bodies Affect Body Repair

Aluminum may seem like an exotic material, but it’s been a part of the auto industry since the turn of the last century, and there’s a good chance your car has at least a few aluminum body parts. Here are some things you probably don’t know about this material.

It’s Been Around a Long Time

The first aluminum-bodied car debuted in 1899, followed by the first production car in 1902. As the industry expanded, aluminum found favor with coachbuilders due to its malleability: if you’re hammering a panel into shape by hand, you want to expend as little effort as possible. This led to a split in the market with regular cars using stamped steel and luxury cars being built from hand-shaped aluminum.

After WWII, aluminum was the material of choice for sports car builders looking to save weight. Land Rover also turned to aluminum for making body panels, first due to post-war steel shortages, and then as a way to prevent rust.

It’s Been a Popular Vehicle Material for Over 20 Years

Widespread use across brands started in the late 90s as automakers look for new ways to improve fuel economy. Since then, aluminum hoods, doors, hatches, and trunk lids have become common, giving automakers a way to save weight without having to redesign the vehicle’s underlying structure.

More recently, manufacturers have started switching over to all-aluminum bodies. Ford was the first company to release an affordable mass-produced aluminum body vehicle with the introduction of the 2015 F-150. This single change let them reduce the truck’s weight by around 800 lbs. Other automakers are following suit with plans for aluminum models from Lexus, Chevrolet, GMC, and Cadillac planned in the next few years.

It Saves Weight and Fuel

Depending on how and where it’s used, aluminum parts can be 10-40% lighter than an equivalent steel part. With less weight to move around, a vehicle will need less power to move and will handle better. Switching to an all-aluminum body can reduce fuel consumption up to 24%.

It’s Safer

Aluminum absorbs twice as much energy as steel in a crash, making it a great material for crumple zones. Switching to aluminum doors adds much-needed crash protection in a limited space and has the added benefit of making them easier to open and close.

It’s Good for the Environment

Aluminum is harder to manufacture than steel, but savings in manufacturing and fuel result in a net decrease in energy consumption over a vehicle’s life. Also, unlike carbon fiber, it’s easy to recycle. Currently, 90% of aluminum in these vehicles is recycled, and this percentage will increase as its use becomes more common.

It’s Not Corrosion Proof

Aluminum doesn’t rust like steel, but it still suffers from galvanic corrosion. This turns pure aluminum into aluminum oxide. As this white powder flakes off, it leaves pits in the panel’s surface. On vehicles, this corrosion separates the paint from the metal, making it bubble. While this was a common issue on earlier aluminum body panels, improvements in coatings has reduced this problem.

Due to the way galvanic corrosion works, mixing metals can speed up the process. If aluminum and galvanized steel meet, the steel will rapidly turn to rust. This makes it crucial to use the right auto repair processes with aluminum: even using a steel bolt to hold an aluminum part can lead to rapid corrosion, destroying the fastener in a few months.

Aluminum Panels Require Different Body Repair Techniques 

Aluminum is sensitive to heat, so automakers rely less on welding and more on adhesives and rivets to attach aluminum body panels. When making a repair, use of heat must be limited to prevent the panel from shrinking or the metal from degrading. Aluminum also doesn’t change color when heated, so its temperature must be constantly monitored during repairs. Welding heat can also melt adhesives used on nearby panels.

The same malleability that made aluminum popular for hand-built cars also requires a lighter touch when fixing dents. When repairing major dents, technicians weld pins to the panel, then pull on these pins to reshape the metal. While a steel panel repair involves a high-power pin welder and slide hammer to reshape dents, technicians use a special low power welder and a lever, gently bending the aluminum panel into shape.

There is one major advantage to aluminum: it takes much less heat to reshape, which allows repairs that would destroy the paint on a steel panel. This can make small repairs far less expensive.

Quality Aluminum Body Repair is Available in Your Neighborhood

Merton Auto Body has the latest equipment, and our technicians receive constant training through the I-CAR Gold Class certification program, so we have the tools and techniques for collision repair, no matter what your vehicle is made of. We’re located a few miles west of I-164 in Sussex, between Lisbon, North Lake and Pewaukee.