How to Finish Exterior Wood With Boiled Linseed Oil

Exterior wood benefits from applying boiled linseed oil.

Exterior wood can rot and wear when exposed to weather, so it's essential to treat decks, fences and wood trim to shield against the elements. Boiled linseed oil -- which is raw linseed oil combined with additives and solvents to speed drying time -- is one of the best preservatives for these surfaces.

Things You'll Need

• Sandpaper or electric sander
• Boiled linseed oil
• Paint thinner
• Paintbrushes
• Stain (optional)

Instructions

1. Start your project when no rain is predicted for several days. Thoroughly sand the wood to create a uniform, porous surface.

2. Apply a wood stain if desired before the boiled linseed oil. If you apply the oil first, its sealant qualities can cause uneven staining.

3. Mix equal parts linseed oil and paint thinner and apply with a paintbrush.

4. Absorb excess with rags as you apply it.

5. Allow to dry for at least 48 hours. Test the surface for moisture and stickiness before touching or walking on it.

Tips & Warnings

• Combine linseed oil with paint thinner to decrease drying time.

• Carefully store rags and paper towels in a pail of water. Since the boiled linseed oil dries through oxidation -- a process which produces heat -- the danger of spontaneous combustion exists.

References

• Jamestown Distributors: Linseed oil
• Richmond Supply Company: Boiled linseed oil
• Popular Woodworking: Oil finishes

Resources

• Sawdust Making 101: Finishing