Oil Finishes: A Natural Approach
Oil finishes penetrate into wood rather than sitting on top like film finishes. They’re easy to apply, forgiving of technique errors, and create a natural look and feel that many woodworkers prefer. Understanding different oils and proper application techniques ensures beautiful, lasting results.
Types of Wood Finishing Oils
- Linseed oil: Derived from flax seeds. Raw linseed oil takes weeks to dry; boiled linseed oil (BLO) dries in 24-48 hours. Adds warm amber tone.
- Tung oil: Harder and more water-resistant than linseed. Slower to cure but more durable.
- Walnut oil: Food-safe option for cutting boards and utensils. Dries slower than other oils but won’t go rancid.
- Mineral oil: Non-drying oil used for cutting boards. Requires regular reapplication as it doesn’t polymerize.
The Wet-Sand Oil Finish Technique
This method produces exceptionally smooth results:
- Sand the wood to 220 grit and remove dust.
- Flood the surface with oil.
- Wet-sand with 400 grit sandpaper while the oil is wet. The slurry of oil and wood dust fills the pores.
- Continue wet-sanding through 600 and 800 grit, adding oil as needed.
- Wipe off excess and allow to dry.
- Repeat for 2-3 coats without wet-sanding on subsequent coats.
Standard Oil Application
- Apply a generous coat with a brush, cloth, or by pouring directly on the surface.
- Let the oil soak in for 15-30 minutes. Reapply to any dry spots.
- Wipe off ALL excess oil with clean rags. This step is critical—oil left on the surface becomes sticky and won’t cure properly.
- Allow to dry completely (24-72 hours depending on oil type).
- Apply additional coats until the wood stops absorbing oil readily.
- Final coat can be buffed with 0000 steel wool for a silky feel.
Safety Considerations
Warning: Rags soaked with drying oils (linseed, tung) can spontaneously combust as the oil cures. Spread used rags flat to dry outdoors, submerge them in water in a sealed metal container, or dispose of them according to local hazardous waste guidelines. Never ball up oily rags and leave them indoors.
