would the resin adhere to our door panels, i have one thats cracked that i want to fix and paint, would it be possible to put fiberglass on the back side over the crack to hold it together?
Yes and no,it will on the plastic sections but you have to drill holes around the area you want to fiberglass. If you have the softer vinyl/rubber parts on the tops of your doors, then it won't stick to that.