Bringing a ’57 Cadillac Eldorado’s Rear Bumpers Back to Life

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These cast aluminum rear bumpers from a 1957 Cadillac Eldorado arrived showing decades of severe corrosion, erosion, and material loss. Once electro-stripped, the true extent of the deterioration became even more apparent. The restoration began with careful grinding and sanding to determine how much of the original aluminum could be saved without distorting the shape of the bumper. Areas that could not be recovered through sanding were marked and sent out for aluminum welding, including deterioration on the face, brackets, and threaded holes on the backside.

Once back from welding, the real shaping work began. The polisher carefully rebuilt the inner diameter and leading edges around the exhaust ports, then used hard blocks and progressively finer abrasives to restore the correct contours and level the welded areas. After the final DA sanding, the bumper ends were ready to begin the plating process. Because they are aluminum, they first went through an acid etch before being treated with Bondall, an adhesion promoter, and then placed in cyanide copper and nickel tanks to establish a proper plating foundation.

Following nickel plating, the bumpers returned to the polishing department for additional DA sanding and a sisal finish before receiving acid copper. The copper layer provided the material needed to continue refining the surface. As the polisher worked through the copper, any remaining imperfections were identified and solder-filled before being sanded smooth and plated again. Once the surfaces were completely level and free of imperfections, the bumpers were ready for final polishing.

Tight areas were polished by hand using compound and a buffing wheel, while the larger surfaces were brought to a mirror finish on a high-speed stand polisher. After a final inspection, the restored bumper ends were ready for their final nickel chrome plating. What began as severely deteriorated cast aluminum had been painstakingly rebuilt, reshaped, plated, polished, and prepared to look right at home on the back of a ’57 Cadillac Eldorado.