Body filler and primer calculator

Film build (how thick the coating actually goes on) depends on volume solids and transfer efficiency the same way for primer as it does for paint or clear coat — using the same physics-based approach that's already the industry standard just applied to primer's specific numbers.

It's the percentage of sprayed material that actually lands and stays on the part rather than overspraying past it or bouncing off — a lower transfer efficiency means you need to buy noticeably more material to reach the same actual film thickness on the part.

Mix only what you can comfortably apply before it starts to set — filler working time is short, and mixing too much at once commonly leads to wasted, hardened material rather than genuinely saving time.