A cracked dashboard indicates a structural issue beyond mere leather or vinyl filler. Furthermore, most dashes are either rigid plastic or vinyl laminated to a thick foam pad. Neither can be sub-patched. A flexible epoxy is the best solution. We recommend SEM Dual-Mix™ Multi-Plastic Repair Material (part# 39847).
- Trim/shave away any lifting edges.
- Fill the crack a little high with the epoxy and smooth with a card.
- Allow to cure for an hour.
- Sand evenly with 220 grit wet-or-dry.
- Repeat until a level surface is achieved.
- Polish with 500 grit wet-or-dry sandpaper.
- Texturize. This epoxy does not emboss well in its uncured state, and sanding may remove your efforts. The easiest is to apply a spray grain. Tiny dots of super glue, patted and dispersed with a paper towel, catalyzed with baking soda, and then sanded can also impart texture. See here. Follow with the spray grain for best results.
- Let each coat of spray grain dry for at least 10 minutes before applying another. Thin coats are better. Gently polish with 500 grit.
- Apply a new color and low-luster clear finish. Spray gun application will get the best result for broad, glaring surfaces like a dashboard.