Here's what we had to start with. This spare tire basket has seen some rough use in its 40+ years of use, and it looks like it lost more than one battle with a curb or low driveway. But there's still plenty of life left in it and with the right material and some TLC it will be back in service as good as new within a few hours.
Materials for this repair: Duramix #4050 SMC/Fiberglass repair compound, the Duramixer applicator gun with mixer/applicator tip, Duramix #4055 Fiberglass-filled Polyester Putty with creme hardener, adhesive-backed fiberglass mesh drywall joint tape, a squeegee/spatula, a 2"x4" strip of plastic cut from a 1-gallon spring water jug, a block sander and a homemade contour sander.
Additional items needed are Eastwood Self-Etching Primer and Satin Black Wheel Paint with aerosol trigger handles, safety goggles, a dust mask and disposable Nitrile gloves. If you have one, a respirator is more desirable but a dust mask is certainly better than no protection at all to keep fiberglass dust from entering your breathing passages.
Start the repair by resting the basket on a workbench so that the crack is resting flat on the surface so we can repair the crack from the inside. A piece of plastic cut from a spring water jug is positioned underneath the crack; the Duramix filler won't adhere to this plastic and will keep the filler from seeping onto the workbench surface.