Seal the Inside of the Barrel
- Fill the barrel to the brim with water.
- Mark any leaking areas on the exterior of the barrel with chalk.
- Empty the barrel of water and allow to dry.
- Apply mastic to the corresponding interior sections of the barrel that match the marked locations of the leaks. Allow mastic to cure according to the manufacturer's specifications.
- Apply a bitumen sealant to the inside of the water barrel using a paintbrush. Let dry for 24 to 48 hours.
Seal the Outside of the Barrel
- Rough up the exterior of the wooden barrel with a medium-grit sandpaper to ensure proper adhesion of the water sealant.
- Apply an even coat of the exterior wood sealant using a paintbrush.
- Allow to dry for six to eight hours.
- Even out drip marks on the first sealant finish using medium-grit sandpaper. Apply a second coat of exterior sealant. Allow to dry.
- Sand out drip marks again and apply a third coat of sealant. Allow to dry.
- Smooth the finish with fine-grit sandpaper.
- Apply a final coat of exterior sealant.