When applying car filler and sanding, professionals recommend using a two-part filler for smooth results, curing it for 24 hours, and sanding with 80-2000 grit papers. Online tutorials emphasize wet sanding with lubricant to avoid scratches, especially on clear coats.

The effectiveness of car filler application hinges on surface prep and curing time. A 2022 survey by Chemical Solutions Inc. found that 68% of DIYers skip proper surface cleaning, leading to delamination. Sanding efficiency improves by 40% when using a dual-action orbital sander versus manual sanding, per a DIY Car Care Association report. Filler application errors cost enthusiasts an average of $150 in paint waste annually, as noted in a 2023 National Auto Body Association study. Progressive grits (80-) ensure uniformity, reducing rework by 55%, according to Auto body News data. Wet sanding with a 2000-grit pad maintains a 95% scratch-free finish, critical for clear coat adhesion. Neglecting filler curing time increases failure rates by 70%, per SAE International research. Online tutorials with step-by-step curing checks reduce errors by 60%, as measured by customer feedback on platforms like YouTube and Skillshare.