Rust can damage the structural integrity of automobiles and other items. If rust remains undisturbed, it will spread and eat away car floorboards and other metal surfaces. Fiberglass is a versatile reinforcing material that contains glass threads, and resin is a reinforced plastic or polymer material. Rust repair kits include liquid fiberglass resin, which is a mixture of fiberglass threads and resin. After the fiberglass resin spreads onto a rust-damaged surface with a brush, it hardens and strengthens the area.
A wire brush or 80-grit sandpaper will remove large flakes of rust from the damaged area, and acetone or soapy water will remove remaining debris, grease and dirt. A liquid rust converter will convert remaining rust to a hard, protective substance called hematite. For proper adhesion, you should sand the hematite before you apply the fiberglass resin. A disposable paint liner or plastic measuring cup is a suitable container for combining the fiberglass resin and hardener. Fiberglass cloth, cut into square pieces and saturated with brushed-on fiberglass resin, fits over and covers the rusted-out area.
The hematite must cure for 24 hours before you apply the fiberglass resin. You must work quickly with the resin and hardener mixture, which remains workable for about 12 minutes. You will save time if you cut pieces of fiberglass mat ahead of time. After application, the saturated fiberglass mat will harden within 1 1/2 to 2 hours at 75 degrees Fahrenheit; it will take longer to dry if the temperature is cooler. After the fiberglass resin hardens, you can sand it down and paint the surface. According to the International Full Size Jeep Association, the rust may return after five or six years in a wet climate.
Fiberglass resin quickly hardens into a durable material that is suitable for rust repair on a wide range of items, including cars, boats, and lawn and garden equipment. Fiberglass resin repair kits are readily available at auto repair stores and in the automotive sections of hardware stores. According to the Jeep Association, do-it-yourself fiberglass resin rust repair is an affordable alternative to more costly repairs at an auto body shop.
When you work with fiberglass, always wear protective rubber gloves and a dust mask to protect your skin and lungs from the short glass fibers. To promote the formation of hematite, remove only the largest rust particles and leave some rust behind. To prevent hardening of unused fiberglass resin, do not put leftover or mixed fiberglass resin back into its original container. Place aluminum tape over the rusted area to prevent fiberglass resin from dripping onto nearby surfaces.
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