Corvette C4, Taking Care of Your Acrylic Targa Roof

Due to my experience manufacturing plastics, I receive many calls and requests on how to care for your C4 Corvette Acrylic Targa Roof. Basic ceiling maintenance goes a long way in increasing the life and appearance of acrylic panel.

For a bit of history, when Chevrolet redesigned the Corvette for its 1984 introduction, they designed a lot of great ideas that had been used on other sports cars in the past. Instead of the T-Top roof panels that had been used on the Corvette C3 from 1968 to 1983, they opted for a Targa roof like the one on the Porsche 911. The standard roof was a fiberglass panel painted the same color as the car. Chevrolet also had an optional sunroof that featured a smoked bronze or blue plastic. Originally, Lexan was used on the roof in 1984, but it was found to scratch easily. Lexan is a very tear resistant material, but the downside to its tear resistance is its soft surface which scratches quite easily. As a side note, every race car uses Lexan for their front windshields, from the local tracks to the Nascar Nextel Cup Series. In the Nextel Cup and Nationwide Series, race teams use release films over the Lexan that can be removed during the race, minimizing windshield scratches. Later, in the 1984 model year, General Motors switched to acrylic with a scratch resistant coating to help prevent scratches to the roof.

Caring for an acrylic ceiling panel is easy. Wash the panel with mild detergent, standard Walmart car wash detergent is fine. The key is to thoroughly spray the ceiling with a hose to remove any loose dirt BEFORE CLEANING THE SOAPED CLOTH. After the ceiling is dry, apply wax to the ceiling. It is important NOT to use a cleaning wax, repeat DO NOT use a cleaning wax as it has abrasives to clean dirt and oxidation on a car paint and will scratch the plexiglass roof. I suggest applying several coats of wax and reapply often as the wax will burn in the sun.

Removing deep scratches from the ceiling is a bit trickier, but if you’re careful and cautious, it shouldn’t be a problem. You first need to sand the scratch with 1200 grit sandpaper. Personally, I use wet/dry paper and wet sand the scratch with water mixed with a little dishwashing detergent. The water acts as a lubricant to help keep surface scratches caused by the sandpaper to a minimum. After this step, dry the area and clean it. If it is a little scratch, you can rub it by hand. Starting with heavy cut lapping compound, buff area with a soft cloth. Then clean it with a finishing polishing compound until all scratches are gone and the shine is gone. The last step is to apply a few coats of paste wax to the ceiling. If the scratch is large, you will need to use a buffing wheel. Before using a buffing wheel, make sure you have experience with it. If not, I suggest you call a car dealer in your area.

For fine surface scratches you don’t need to use sandpaper, just lightly buff the ceiling by hand with a scratch removal compound, such as Maguire’s. It may take some time, so be patient.