A composite formulation for use in lightweight molded components includes an untreated low density filler, such as glass bubbles, a solvated polymer mixture, and polymer paste. In one embodiment the solvated polymer mixture is used to treat the low density filler to form a treated low density filler. The solvated polymer mixture many include a thermoplastic resin or a reactive resin and an additive package. The additive package may include a dispersing agent and a silane carrier composition.