Today, more manufacturers are coming to market with aluminum structures than ever before. While we used to consider an aluminum structure exotic, more aluminum is arriving in vehicles at a quick pace.

It’s easy to see why.While using aluminum parts to replace steel can give a weight savings of 40-50 per cent, if the structure is designed with aluminum characteristics from the beginning a weight savings of up to 65 per cent is possible.

Characteristics of aluminum are not only the weight considerations, but good corrosion characteristics when properly maintained and designed.

Aluminum has a natural corrosion effect which protects itself with an oxidation film when it is exposed to the elements. This oxidation occurs naturally immediately after the material is cleaned.

This corrosive effect can be accelerated when aluminum and steel contact each other, and is known as galvanic corrosion.

Repairs to aluminum can be affected if steel and aluminum come into contact. This contact can be from tools, or environmental issues that must be maintained in order to prevent this type of contamination.

Because of atmospheric effects of aluminum compared to steel the vehicle needs to be protected from contaminants in the air.

These contaminants (mainly airborne metal grindings) can find their way into pinch welds, panel seams, and joints. For this reason aluminum repairs should be performed in an area separate from other repairs.

Some manufacturers require a clean room sort of like a spray booth, while some manufacturers require curtaining to contain the area during the repair. All manufacturers do agree that the tools used on aluminum must be separated from those used on steel.

The tools should be contained in a separate area and stored away from tools contacting steel. Even basic hand tools, sockets, and body hammers that contact aluminum should not be mixed with tools used on steel. This ‘clean room’ also needs plenty of ventilation to maintain air mass, and high intensity lighting as you would have in a spray area.

Structural Repair

Repairs can vary by OEM manufacturer, ranging from adhesive, to rivets, to welding. All manufacturers also agree that special equipment is required to perform these repairs.

Parts placement requires universal or dedicated fixture systems on a milled bench to hold parts in place for adhesive curing or welding. Because of the rocker, panel design of the Jaguar requires special pinch weld clamps that have been designed to compensate for the rivets placed in this area. Audi and BMW also require special clamping because of rocker design in order to hold them to the bench system.

Individual repair processes depend on the manufacturer. While BMW relies on replacement of affected areas with procedures using adhesive and rivets, Jaguar utilizes GMAW (mig) welding and rivets depending on repair area. Audi again relies on welding in most locations. All vehicles have crush zones designed in the rail ends which typically require replacement.

BMW, for instance has four procedures for replacement on the aluminum front section of the 5 and 6 series vehicles. A lower rail tip, upper radiator support section, complete lower rail, and complete upper apron and strut tower.

Each procedure requires vehicle specific training to insure the repair is performed to correct standards. BMW offers model specific training to all BMW dealer collision facilities, and/or independents sponsored by the dealer. This training utilizes the tools, parts and processes to complete all four repairs. BMW also states no pulling on the aluminum portion of the vehicle.

Audi, which has been repairing aluminum on the A8 for the longest period of time, has elected to set up facilities across North America and the vehicles are transported by the manufacturer to one of the certified facilities. Audi has partnered with I-CAR to help with the needed technician model
specific training.

Jaguar also has elected to set up certified facilities for repair in two classifications: Non-Structural and Structural. The Non-Structural facility can perform repairs that do not require structural panel adjustment or replacement. The Structural shops are outfitted with special equipment to fixture parts in place and a welder that has specific parameters.

Both the Structural and Non-Structural facility must meet special requirements and have equipment that is approved by Jaguar for the repair.

One of the problem characteristics of aluminum is the cracking of material. Depending on the specific material, it can be porous and crack as pulling is performed. Aluminum simply does not have the same elasticity of steel.

Sometimes low heat can be used from an induction heater to warm the area prior to moving the material a minimal amount. The adjoining areas connected can be affected by the movement. Adhesives and rivet strength can be affected by the movement. Individual vehicle manufacturers dictate how much (if any) pulling can be performed.

Many current models of vehicles contain aluminum hoods and deck lids, on the average vehicle that can have small damage that can be repaired following correct processes instead of the costly replacement of the part.

This is a hot topic with insurance companies and collision facilities. Two necessary factors are readily available tools and proper training.

Where will aluminum go in the future? Manufacturers are still weighing out the possibilities of this material.

One thing is for sure. Don’t expect it to go away anytime soon. Nor should you expect a disappearance of steel. Steel manufacturers are not going to walk away without a fight, and they are bringing lighter, stronger materials to the table on a continuous basis.

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