Plastex Plastic in Vette Magazine

Plastex in Vette Magazine


Since Corvette bodies are made of a different material than most other production cars, repairing minor damage can require alternative materials and techniques. While fiberglass and SMC (Sheet Molded Compound, which is found on later models) have the advantage of being rustproof, such composites are subject to their own sets of problems. These range from crazing (also called "spider webbing") to cracking, usually from a slight impact. More-severe or widespread body damage may require the complete replacement of large components -  a job best left to pro - so we'll limit our focus on minor damage that can be repaired in your own driveway.

Fiberglass plastic repair

We'll start with a slight surface imperfections. If polishing and waxing isn't producing the smooth finish you'd like to see on your beloved Corvette, consider using 3M Scratch Remover, which is designed to minimize defects that don't penetrate the clearcoat (assuming your vehicle has a two-part urethane paint). This product is fairly simple to use, requiring only three separate steps and common household drill. We tried the 3M product on a C5 that had a few scratches on it, and they all but disappeared.
For cracks or crazing (the latter is usually seen on older fiberglass bodies), a type of adhesive called Plastex can repair a wide range of materials. In addition to fixing fiberglass or SMC, it can be used to fabricate small components, or even metal (using a slightly different version of the repair kit).
The inventor of Plastex, Tim Lewis of G.T. Motorsports, has some pretty impressive credentials in chemical engineering. In addition to being trained at the Northrop Institute of Technology, he's worked on the adhesive tiles used on NASA's space shuttle, and served as manager of Harrah's car collection. So he knows his way around composite materials and hot to take are of fine automobiles.
Using Plastex is a straightforward process, easier than working with resin and fiberglass. Unlike conventional resin and catalyst, form most repairs the mixing ration doesn't have to be in  precise proportions, as long as the powder is thoroughly saturated. Depending on the type of damage, Plastex powder can be used with or without the cloth included in the kit, and it dries very quickly in a variety of weather conditions, so that you can sand it and prep for paint in short order.

Vette Magazine and plastic repaire

* Fine crazing - also known as "spiderwebbing" - can occur in older fiberglass due to age, weathering, and slight impacts.
* Plastex can be used to repair just about any type of Corvette panel, from traditional fiberglass to urethane to SMC. (Highly flexible parts might require another type of Plastex kit.) This particular fender panel had a slight crack, but we bent it open more for purposes of illustration.
* To ensure a good bond, start by roughing up the inner surface of the area to be repaired.
* Apply painter's tape to the outside area of the crack or hole.
* The Plastex kit consists of three bottles of acrylate powder (clear, white and black, and colored additives are available for matching hues), a liquid hardener (methyl acrylate monomer), and a special untreated, non-reactive fiberglass cloth, which can be used on larger repairs.
* Applying the powder can be done in a couple of different ways, depending on the type of repair. For smaller damage, or vertical surfaces, first squeeze some powder into a small cup (provided in the kit).
* Pour the hardener into a smaller bottle, and cap it with applicator tip.
* Add a couple of drops of hardener to the powder, but don't saturate it completely, as you'll use the applicator tip to pick up a small droplet.
* Place the droplet into the crack and let dry.
* Alternatively, you can sprinkle the powder directly into the crack or hold to be repaired (as long as it can be laid horizontally, so the powder doesn't fall out).
* Saturate the powder thoroughly. You don't need to measure the ratio; just make sure it's wetted completely.
* Allow the mixture to dry, checking by touch after 15 minutes or so.
* Remove the tape from the outer surface of the part.
* Use the Dremel or other dine grinder to create a groove in the surface. The following steps also apply to repairing crazing or surface cracks on fiberglass.
* Apply powder (or wet droplets) to the groove in the outer surface.
* Make sure the powder is completely saturated with hardener.
* Use the spreader to force the mixture into the groove and even out the surface.
* After the mixture dries, sand the surface evenly until smooth, and then prep for paint.