by Lars Grimsrud Colorado Corvette Crazies (CCC) The Ultimate Corvette Tuning & Beer Drinking Fraternity Lafayette, CO Rev. C 1-12-03 This tech paper will discuss simple repair (non-structural) and refinishing processes to produce high-quality results on fiberglass (Corvette) panels. Recognize that there are many different product lines out there, and severalwork techniques for accomplishing body repairs. Different auto body professionals have different preferences as to how to do things, and I may get some disagreement on the specifics of this article. This article will provide you with a group of products and materials, and my personal technique, for accomplishing first-class results.
General ‘Vette Info
Two different construction techniqueshave been used to manufacture Corvette body panels over the years. When the ‘Vette made its debut, the new “FRP” body was a major innovation. “Fiberglass Reinforced Plastic” was a construction method that could be used to make lightweight panels with curves and design features that could not be easily duplicated in stamped steel. The body was basically built just like a fiberglass swimming pool or aboat hull: A “chopgun” was used to blow fiberglass strands and resin into a mold that was first coated with resin to produce a smooth surface finish on the body parts. This technique was used through the 1981 model year. 1982 was a unique transition year in many respects. Fuel injection was added to the ‘Vette, and a computer was installed to manage all major engine functions. ’82 also saw theadvent of a revised body panel construction. “Structural Matted Components,” or SMC panels, were thinner and lighter due to a laminate construction using more plastic and less ‘glass. This panel type is used on all of our C4 ‘Vettes, and partially on the groundbreaking ’82. The composite materials on all ‘Vettes require use of specific techniques and materials. Treating a ‘Vette like a steel car cancause irreparable damage to the body: metal paint stripping techniques cannot be used, and fillers designed for use on steel will not adhere properly to the FRP or SMC panels. So read on to get the real scoop on the right stuff to use….
Body shops use a lot of air-powered tools in order to speed up repairs and improve profits. All cosmetic bodywork can be performed without theuse of air tools, and you will often get better results due to the slower progression of the work. You will, however, need a paint gun, and you’ll need compressed air to power it.
Hand Tools Needed
File Board A File Board isn’t a file at all: it’s a long backing board with handles for mounting long strips of sandpaper, called “file sheets.” The length and stiffness of the file board allows youto produce perfectly smooth, straight panels and repairs. It’s the most important tool you’ll use in the repair and refinishing of your ‘Vette. The most common Boards are molded hard rubber, and require use of sticky-backed sandpaper. I personally prefer the old style wooden ones with metal clips securing the sandpaper: they allow me to use either sticky-backed or standard sandpaper. Cost of awooden File Board with clips is about $25. They are available at all body and paint supply stores. The long ones, which I highly recommend, are 16” long and 2-1/2” wide. Sanding Block In addition to your File Board, you’ll need a small, rubber sanding block. These soft, flexible black rubber blocks are about 3/8” thick, and measure 2-1/2” wide by 5” long. These dimensions allow you to tear apiece of standard sandpaper in half and wrap it perfectly around this semi-flexible block. You’ll use it to do all of your finish sanding and color sanding (discussed later). Filler Handling/Mixing Tools To mix and apply any body fillers, you’ll need a flat plate and a spatula/spreader. Flat plastic/nylon mixing plates and spreaders are available from your body & paint supply store, but I just use a...