How To Fix Cracks In Dashboard

Dashboard cracks. They're the bane of every car owner's existence, a constant reminder of sun exposure, age, and sometimes, just plain bad luck. A cracked dashboard doesn't just look bad; it can impact resale value and, in extreme cases, even affect safety by reflecting sunlight into your eyes. This article will guide you through the process of repairing those unsightly cracks, providing you with the knowledge and techniques to achieve professional-looking results.

Understanding Dashboard Materials

Before diving into repairs, it's crucial to understand what you're dealing with. Most dashboards are constructed from thermoplastics, primarily Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Chloride (PVC), or Polypropylene (PP). Some higher-end vehicles might use leather or vinyl-wrapped dashboards over a rigid core. The specific material dictates the repair methods and products you should use.

• ABS: Known for its impact resistance and rigidity. Common in older vehicles.
• PVC: Flexible and resistant to UV degradation, often used in dashboards exposed to direct sunlight.
• Polypropylene: Lightweight and resistant to chemical solvents, becoming more prevalent in modern cars.
• Vinyl/Leather: Requires specialized repair techniques and materials due to its porous nature.

Identifying your dashboard material is critical. You can usually find this information in your vehicle's service manual or by contacting the manufacturer. If unsure, test a small, inconspicuous area with different repair products to observe their reaction before applying them to the entire crack.

The Technical Breakdown: How Dashboard Cracks Form

Dashboard cracks are primarily caused by thermal expansion and contraction. Think of it this way: the dashboard heats up significantly under the sun's rays, causing the plastic to expand. As the temperature cools, the plastic contracts. Over time, this constant expansion and contraction weakens the material, leading to stress cracks. UV radiation further exacerbates this process by breaking down the chemical bonds within the plastic, making it brittle and susceptible to cracking.

Another common cause is plasticizer migration. Plasticizers are chemicals added to plastics to make them more flexible. Over time, these plasticizers can evaporate or migrate to the surface, leaving the plastic brittle and prone to cracking. Think of an old vinyl record – it becomes hard and brittle as it ages, that's due to plasticizer loss.

Finally, physical stress, such as leaning heavily on the dashboard or placing heavy objects on it, can also contribute to crack formation.

Repairing Dashboard Cracks: A Step-by-Step Guide

Here's a detailed process for repairing those cracks, assuming we're dealing with a typical thermoplastic dashboard:

1. Preparation is Key

Cleaning: Thoroughly clean the area around the crack with a degreasing cleaner and a soft brush. Remove any dirt, dust, or loose debris. This ensures proper adhesion of the repair material.

Masking: Use painter's tape to mask off the area around the crack, protecting the surrounding dashboard from accidental damage or overspray.

V-Grooving (Optional but Recommended): For wider cracks, use a rotary tool (like a Dremel) with a small V-shaped bit to carefully widen the crack into a V-groove. This provides a larger surface area for the repair material to bond to and creates a stronger, more durable repair. Exercise extreme caution when using a rotary tool, as it's easy to accidentally damage the surrounding dashboard. Start with a slow speed and gradually increase it as needed.

2. Filling the Crack

Filler Selection: Choose a flexible filler specifically designed for automotive plastics. Two-part epoxy fillers are generally the strongest and most durable, but they require careful mixing and application. One-part fillers are easier to use but may not be as strong. Consider a product like SEM Flexible Bumper Repair or 3M Automix Flexible Parts Repair.

Mixing (if using a two-part filler): Carefully mix the filler components according to the manufacturer's instructions. Use a clean mixing surface and disposable applicators to avoid contamination.

Application: Apply the filler to the crack, pressing it firmly into the groove to ensure good adhesion. Overfill the crack slightly, as the filler will shrink slightly as it cures. Use a flexible spatula or plastic spreader to smooth the filler surface and remove any excess.

Curing: Allow the filler to cure completely according to the manufacturer's instructions. This may take several hours or even overnight.

3. Sanding and Smoothing

Sanding: Once the filler is fully cured, sand the surface smooth using progressively finer grits of sandpaper. Start with 180-grit to remove the bulk of the excess filler, then move to 320-grit, and finally 400-grit to create a smooth, even surface. Use a sanding block to ensure even pressure and avoid creating low spots.

Feathering: Feather the edges of the repair area to blend it seamlessly with the surrounding dashboard. This involves gradually reducing the pressure on the sandpaper as you approach the edges of the repair.

4. Texturing (Optional but Highly Recommended)

Most dashboards have a textured surface. Replicating this texture is crucial for a professional-looking repair. Several methods can be used:

• Texture Pad: These pads are designed to imprint a specific texture onto the filler while it's still slightly tacky.
• Texture Coat Spray: These sprays create a textured surface that can be applied after the filler has cured.
• Stippling: Using a brush or sponge, apply the filler in a stippling motion to create a textured surface.

Choose the method that best suits your dashboard's texture and the type of filler you used. Practice on a scrap piece of plastic before applying the texture to the repaired area.

5. Painting and Blending

Primer: Apply a thin coat of automotive primer to the repaired area. This provides a uniform surface for the paint to adhere to and helps to hide any imperfections.

Color Matching: The most critical step is accurately matching the color of your dashboard. Take a sample of your dashboard (e.g., a small piece of trim) to an automotive paint supplier for color matching. They can use a spectrophotometer to analyze the color and create a custom-mixed paint.

Painting: Apply several thin coats of paint to the repaired area, allowing each coat to dry completely before applying the next. Use a spray gun for the best results, but aerosol cans can also be used if you're careful. Hold the spray gun or aerosol can at a consistent distance from the dashboard and move it in smooth, even strokes.

Blending: Blend the paint into the surrounding dashboard by gradually reducing the pressure on the spray gun or aerosol can as you approach the edges of the repair. This will help to create a seamless transition between the repaired area and the original dashboard.

6. Clear Coat (Optional)

Applying a clear coat can provide additional protection and enhance the gloss of the repaired area. Choose a clear coat that is compatible with the paint you used. Apply several thin coats, allowing each coat to dry completely before applying the next.

Common Issues and Maintenance Concerns

• Filler Shrinkage: Some fillers shrink as they cure, creating a depression in the repaired area. To avoid this, overfill the crack slightly and allow the filler to cure completely before sanding.
• Color Matching Difficulties: Achieving a perfect color match can be challenging. Work with a reputable automotive paint supplier and be prepared to experiment with different shades.
• Texture Replication: Replicating the dashboard's texture can be tricky. Practice on a scrap piece of plastic before applying the texture to the repaired area.
• UV Protection: After the repair, consider applying a UV protectant to the entire dashboard to prevent future cracking.

Do's and Don'ts / Best Practices

Do's:

• Do identify your dashboard material before starting the repair.
• Do thoroughly clean the area around the crack.
• Do use a flexible filler specifically designed for automotive plastics.
• Do sand the repaired area smooth using progressively finer grits of sandpaper.
• Do replicate the dashboard's texture.
• Do accurately match the color of your dashboard.
• Do apply several thin coats of paint.
• Do use a UV protectant after the repair.

Don'ts:

• Don't use a rigid filler, as it will crack easily.
• Don't apply too much filler at once.
• Don't sand too aggressively, as you could damage the surrounding dashboard.
• Don't use household paint, as it will not adhere properly.
• Don't skip the color matching step.
• Don't apply thick coats of paint, as they will run and sag.

Conclusion

Repairing dashboard cracks is a challenging but rewarding DIY project. By understanding the materials involved, following the steps outlined in this article, and taking your time, you can achieve professional-looking results and restore the appearance of your vehicle's interior. Remember to prioritize preparation, use high-quality materials, and pay attention to detail. If you're unsure about any aspect of the repair process, consider seeking professional assistance. A cracked dashboard is an eyesore, but with the right knowledge and techniques, you can bring it back to life and enjoy a more comfortable and aesthetically pleasing driving experience. The most important part is the preparation to have a smooth process.