ABS (short for Acrylonitrile butadiene styrene) is a thermoplastic. It's used with many items, including musical instruments, plastic pipes and the outer shells of sports motorbikes. Fibreglass is tougher than ABS and therefore more hard-wearing. You can use it to strengthen ABS by gluing fibreglass to the back of an ABS panel. If you have damaged bodywork or want to glue ABS to fibreglass for another reason, you need a glue that will adhere to ABS. There are several methods you can use to attach ABS to fibreglass.
Clean the area you want to glue. You can use a special cleaner but if you don't have one, soapy hot water will also work.
Roughen the surfaces you want to glue using a wire wheel on top of an electric drill. Roughen the individual surfaces separately and try to catch any ABS shavings or dust for later use.
Apply a layer of methylene chloride acrylic cement to the ABS and fibreglass and quickly stick the two sheets together. This product is available from your local hardware or craft store. It temporarily liquefies the surfaces of the plastics, then causes them to harden again, making them more likely to mix and bond.
Mix a two-part filler or epoxy that is compatible with fibreglass. Apply it to the surface you want to glue using a squeeze bottle with a hollow needle if necessary. This will help the glue get to the hard-to-reach parts and strengthen the bond between the ABS and the fibreglass.
Wait for the epoxy to dry and the fibreglass should be stuck to the ABS. At this stage, you can strengthen the bond further if necessary by mixing the ABS shavings from earlier with some of the methylene chloride acrylic cement. This creates a glue that you can apply to any remaining cracks or unsealed edges. Once the cement has hardened, you can finish treating or decorating the ABS and fibreglass as you wish.
Always use epoxy resin and methylene chloride acrylic cement in a well ventilated area.