If body filler is not mixed properly, what is a likely outcome?

• A. The filler may not cure properly and may lack strength
• B. The color will change
• C. It will become lighter
• D. It will evaporate

Answer: (A)

Body filler cures through a chemical reaction between the resin and the hardener, and the right mixing ratio is essential for that reaction to proceed fully. When it isn’t mixed properly, the cure can be incomplete, so the filler never reaches its intended hardness. That leaves the repair soft, weak, and more prone to dents, cracking, and adhesion failures after it’s covered with putty, primer, and paint. It also sands poorly and may not hold up over time.

Color change, lightening, or evaporation aren’t typical issues caused by improper mixing, since those outcomes aren’t driven by the cure chemistry in the filler.