Oak beams are found in many older houses, but over time they can take on a dark, dingy look as they accumulate dirt and dust, especially because oak is an open-pored wood that easily holds dust in its pores. By taking the time to restore oak beams, you can transform them from blah to a major architectural feature of any room.
Clean the beam using a solution of four parts water to one part ammonia. Use a clean, lint-free cloth and rub the beam from one end to the other. If the beam is rough sawn, use a soft-bristled scrub brush.
Remove built-up, stuck-on grime by using the same ammonia mixture and a green Scotch-Brite pad. Alternatively, use white spirit instead of the ammonia. One will generally work better than the other.
Remove the finish with a commercial finish remover. If the wood is only clear-coated, try denatured alcohol, white spirit and lacquer thinner. Follow the directions on the finish remover, as they vary from brand to brand and even product to product within the same brand.
Mix equal parts mineral or tung oil and boiled linseed oil and flood the surface of the newly stripped beams. Allow to set for several minutes, and remove the excess by wiping the surface down with a clean cloth. This will recondition the wood by allowing the oils to soak in and replace any dried-out oils that are naturally occurring in the oak.
Stain the oak beam, if desired. Flood the surface with stain, and allow it to sit for a minute or two. Then wipe the excess off with a clean cloth. Repeat the process to get a darker look.
If gouges or scratches are present in the wood, use a filler that is designed to match the stain colour applied. Do this after the stain is dry but before applying the top coat for some brands and after applying the top coat for others. Read the packaging to determine which type you are dealing with.
Finish the restoration with a top coat that is compatible with the stain. For lacquer, using an airless sprayer is the best way to apply it. Other finishes may be brushed on, but spraying would also prove beneficial.
To remove small dings from the wood, use an eye dropper to fill the ding with water. Sometimes the water will swell the wood and even out the ding. Boiled linseed oil is available at most paint and home improvement stores and comes ready to use.