Like genuine leather, vinyl cracks as it ages and desiccates (dries out). Unlike leather, however, the cracks often create sharp edges that curl upward and stand above the surrounding surface. Even the most skillful repairs often result in a slightly elevated mound. Bear in mind also that if the original vinyl cracked, a repair cannot be expected to last any longer. It may be just as expensive to reupholster or replace the component.
But if you borrow a heat gun and buy some graining papers, you’ll get a better result (so long as the vinyl is not a flimsy variety that shrinks with heat). If you plan to make this a hobby or vocation, invest in a graining kit to make your own.
The graining kit includes a compound and a catalyst. Mix these together and pour onto an undamaged horizontal surface and allow to cure (about 20-30 minutes). You’ll have a strong, floppy, heat resistant pad with a negative of the material’s grain that can be used to emboss the filler as it cools. Buy only as much as you need, as it spoils rather quickly. Or commit to making a variety of grains. They will last decades!
Here’s how to repair cracking vinyl with a heat gun and grain pad:
- Subpatch any holes.
- Holding a clean, new razor blade almost parallel to the surface, carefully shave away any sharp, curling edges that stand high above the surface.
- Those too low-profile or risky to shave can be gently melted with the heat gun ~550°F at a distance of 2-6″ and immediately pressed with the grain pad (we’ve even ‘nuked’ some heavier duty vinyls with 1000°F and a reducer nozzle, but be cautious).
- Before the vinyl cools, apply the grain pad and press with a small board or block to exert even pressure and avoid dents in the upholstery. The surface needs to be room temperature and as level as possible before filler is applied.
- Clean the surface with denatured or rubbing alcohol.
- Use a heat-cure filler like SEM Leather & Vinyl Repair Compound. The application process is similar to that of Soft Filler: apply a thin coat, level and remove excess with a plastic spreader or card.
- Rather than letting it air dry, however, use the heat gun ~550°F a distance of 8-10″ from the repair and warm until the filler begins to change from a glossy white cream to a more translucent, frosted appearance. If it gets very hot, it will go glassy again, which will actually receive the grain better, but careful not to melt the surrounding area.
- Immediately apply the grain pad and block with gentle, even pressure to the repair area for a few seconds. This will emboss the filler as it cools.
- Allow the surface to return to room temperature before continuing. Some pros invest in a chill block, but water and a few minutes will do the trick.
- Repeat steps 4-7 until the surface feels even.
- If necessary, do a thin final coat of filler, texturize with a gloved hand to blend lines, heat, and emboss with grain pad.
- You can also use a spray grain like SEM Chip Guard to further blend texture.
- Apply Rub ‘n Restore® color and Clear Prep+Finish™ if desired.
- If the repair needs, re-working, use Flite™ or rubbing alcohol to remove the color before applying more filler.