How To Fix A Dash Crack

A cracked dashboard is more than just an eyesore; it's a sign of age, wear, and often, neglect. Beyond aesthetics, cracks can devalue your vehicle, reduce structural integrity in a collision, and even become a safety hazard if pieces break off and obstruct your vision. Fortunately, with the right tools, materials, and a little patience, you can repair a dashboard crack yourself and restore your car's interior to its former glory. This article provides a detailed guide for intermediate car owners and DIY mechanics to effectively fix dashboard cracks.

Understanding the Dashboard: A Technical Overview

The dashboard, or instrument panel, is a complex assembly composed of various materials and components. To effectively repair a crack, understanding its construction is crucial.

Dashboard Materials

Most dashboards are constructed using a combination of:

• ABS Plastic (Acrylonitrile Butadiene Styrene): This is the most common material due to its durability, impact resistance, and relative affordability. ABS plastic is typically vacuum-formed to create the dashboard's shape.
• Polyvinyl Chloride (PVC): Often used for the dashboard's surface layer, providing a soft-touch feel and resistance to UV degradation. However, PVC can become brittle and crack over time, especially with prolonged sun exposure.
• Foam Padding: Located beneath the surface layer to provide cushioning and impact absorption. This foam can deteriorate over time, contributing to surface cracking.
• Reinforcing Structures: Metal or plastic supports are integrated within the dashboard to provide structural rigidity and attachment points for instruments, vents, and other components.

Causes of Cracking

Dashboard cracking is primarily caused by:

• UV Exposure: Ultraviolet radiation from sunlight breaks down the chemical bonds in the dashboard materials, causing them to become brittle and susceptible to cracking.
• Heat: Extreme temperature fluctuations can cause the dashboard to expand and contract, leading to stress and eventual cracking.
• Age: Over time, the plasticizers in the dashboard materials evaporate, causing them to harden and crack.
• Impact: Physical impacts, even minor ones, can initiate cracks, especially in areas already weakened by UV exposure or heat.
• Stress Concentrations: Areas around vents, speakers, and instrument clusters are often subject to higher stress levels, making them more prone to cracking.

Repairing the Crack: A Step-by-Step Guide

This process outlines the steps involved in repairing a dashboard crack, assuming the crack is not structurally compromising the dashboard. For severe damage, professional repair or replacement may be necessary.

1. Preparation and Assessment

Before you start, gather your tools and materials:

• Dashboard Cleaner: To remove dirt and grime.
• Sandpaper: A range of grits (120, 220, 400) for preparing the surface.
• Plastic Repair Kit: Includes a plastic filler, hardener, and applicator tools. Look for kits specifically designed for automotive dashboards. Epoxy resins are a good choice, but ensure they are flexible after curing.
• Razor Blade or Utility Knife: For cleaning up edges.
• Masking Tape: To protect surrounding areas.
• Color-Matching Paint or Dye: To blend the repair with the existing dashboard color. Consider using a spectrophotometer for accurate color matching.
• Primer: For plastic surfaces.
• Clear Coat (Optional): For added protection and shine.
• Heat Gun or Hair Dryer: To speed up drying times (use cautiously!).
• Safety Glasses and Gloves: To protect yourself.

Carefully assess the crack. Determine its depth, length, and surrounding damage. Clean the area thoroughly with dashboard cleaner and a microfiber cloth. This removes contaminants that could interfere with the repair.

2. Crack Preparation

Use the razor blade or utility knife to carefully remove any loose or crumbling pieces of plastic around the crack. Be gentle to avoid creating further damage. Use 120 grit sandpaper to create a shallow "V" groove along the crack line. This provides a larger surface area for the plastic filler to adhere to. The "V" groove is crucial for a strong bond; it’s a mechanical interlock.

Next, use 220 grit sandpaper to smooth out the edges of the "V" groove and blend it with the surrounding surface. Wipe away any sanding dust with a tack cloth or a clean, damp cloth.

3. Applying the Plastic Filler

Follow the instructions provided with your plastic repair kit to mix the plastic filler and hardener. Typically, this involves combining two components in a specific ratio. Work quickly, as the mixture will start to harden within a few minutes.

Use the applicator tool to carefully fill the crack with the plastic filler. Overfill slightly to allow for sanding. Ensure the filler penetrates the "V" groove and bonds with the surrounding plastic. For deeper cracks, apply the filler in thin layers, allowing each layer to cure before applying the next. This prevents air pockets and ensures a stronger repair. Using a spreader can help achieve an even application.

4. Sanding and Shaping

Allow the plastic filler to cure completely according to the manufacturer's instructions. Once cured, use 220 grit sandpaper to carefully sand down the excess filler until it is flush with the surrounding surface. Be patient and avoid sanding too aggressively, as this could damage the surrounding dashboard. Switch to 400 grit sandpaper to further smooth the surface and remove any scratches left by the coarser grit. Feather the edges of the repair to seamlessly blend it with the surrounding dashboard.

Wipe away any sanding dust with a tack cloth.

5. Painting and Finishing

Apply a thin coat of plastic primer to the repaired area. This will help the paint adhere properly. Allow the primer to dry completely according to the manufacturer's instructions.

Apply several thin coats of color-matching paint or dye to the repaired area, allowing each coat to dry completely before applying the next. Use light, even strokes to avoid runs or drips. If using an aerosol can, hold it about 8-10 inches away from the surface. Consider using a tack coat – a very light first layer – to promote adhesion.

Once the paint has dried completely, apply a clear coat (optional) to add protection and shine. Follow the same application technique as with the paint. Let the clear coat dry completely.

6. Final Touches

Remove the masking tape and inspect the repair. If necessary, use a polishing compound to further blend the repaired area with the surrounding dashboard. Reinstall any components that were removed during the repair process.

Common Issues and Maintenance Concerns

• Filler Shrinkage: Some fillers shrink as they cure, requiring multiple applications. Choose a high-quality filler specifically designed for automotive use.
• Color Matching Difficulties: Achieving a perfect color match can be challenging. Take your time and experiment with different paint mixtures until you find a close match. Test the paint in an inconspicuous area first.
• Uneven Texture: Matching the texture of the original dashboard can be difficult. Experiment with different sanding techniques and texturing tools to achieve a seamless blend.
• Cracking Reoccurrence: If the underlying cause of the cracking (e.g., excessive heat) is not addressed, the crack may reappear. Use a sunshade when parking in direct sunlight and consider applying a UV protectant to the dashboard regularly.

Do’s and Don’ts / Best Practices

Do’s:

• Do wear safety glasses and gloves to protect yourself from chemicals and dust.
• Do work in a well-ventilated area.
• Do use high-quality materials specifically designed for automotive use.
• Do take your time and be patient. Rushing the process will likely result in a subpar repair.
• Do thoroughly clean and prepare the surface before applying any filler or paint.
• Do apply the filler and paint in thin layers.
• Do allow each layer to dry completely before applying the next.
• Do use a sunshade to protect your dashboard from UV exposure.
• Do consider applying a UV protectant to the dashboard regularly.

Don’ts:

• Don’t use excessive heat to speed up drying times. This could damage the dashboard or cause the filler to crack.
• Don’t sand too aggressively, as this could damage the surrounding dashboard.
• Don’t apply the filler or paint in thick layers. This could result in runs, drips, or uneven drying.
• Don’t ignore underlying causes of cracking, such as excessive heat or UV exposure.
• Don’t attempt to repair severe damage without professional assistance.

Conclusion

Repairing a dashboard crack is a manageable project for the experienced DIYer. By understanding the materials involved, following a careful process, and using the right tools and techniques, you can significantly improve the appearance and value of your vehicle. While this guide provides a comprehensive overview, remember to consult the specific instructions provided with your chosen repair kit and paint products. If you’re uncomfortable with any aspect of the repair, seeking professional assistance is always a prudent option. For minor cracks, this DIY approach can save you significant money and restore your car's interior to a more presentable condition. Good luck, and drive safely!