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How do you sand and prep a car?

Published in Car Painting Prep 3 mins read

Sanding and prepping a car is a crucial step before applying new paint or coatings. Here's a breakdown of the process:

Sanding Process

The goal of sanding is to remove imperfections, rust, and prepare the existing paint surface for proper adhesion of new coatings. Here's how to do it:

  1. Initial Sanding:

    • Begin by dry sanding with 180-grit sandpaper.
    • This step is essential for removing rust, surface damage, and any deep scratches.
    • Work in consistent strokes, and don't apply excessive pressure.

  2. Smoothing Out:

    • After the initial sanding, switch to 320-grit sandpaper.
    • This grit will remove the scratches left by the 180-grit paper.
    • Continue sanding until the surface feels smooth to the touch, ensuring all 180-grit scratches are gone.

  3. Final Surface Prep:

    • The last step is to sand with 400- to 600-grit sandpaper.
    • This final sanding step is essential for preparing the existing paint for new coatings.
    • The goal is to create a surface with enough 'tooth' for the new paint to grip without being too rough.

Prepping the Car

Beyond sanding, there are some additional steps to prep the car:

  • Cleaning:

    • Thoroughly clean the vehicle with a degreaser and soap to remove any residual sanding dust, dirt, and grease.
    • Rinse thoroughly and let it dry completely.

  • Taping:

    • Mask off any areas you don't want to paint using high-quality painter's tape and masking paper.
    • Ensure the tape is adhered securely to prevent paint bleeding.

  • Inspection:

    • Once the car is dry, carefully inspect the sanded areas for any remaining imperfections.
    • If necessary, go back over areas with finer grit sandpaper for a perfectly smooth surface.

Summary of Sanding and Prepping a Car:

Step Grit Purpose
Initial Sanding 180-grit Removes rust, surface damage, deep scratches.
Smoothing 320-grit Removes scratches left by 180-grit sandpaper.
Final Prep 400-600 grit Prepares the surface for new coatings, creates a slight texture for adhesion
Cleaning N/A Removes dust and residue before painting.
Taping N/A Masks areas you don't want to paint.
Final Inspection N/A Checks for imperfections before applying coatings.

By following these steps, you will create a smooth, clean surface that is ready for new paint or coatings.

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