Outdoor furniture made of cedar wood is generally prized for its attractive color, grain structure and a natural ability to repel insects. Over time, unfinished outdoor cedar furniture will weather to become a silver-gray color. However, a cedar swing set or other piece of cedar lawn furniture can be treated using one of a number of finishes. Regardless of the type of finish utilized, the cedar wood should be properly cleaned and prepared prior to application.
Clear sealers and semi-transparent stains bring out the color of cedar wood while maintaining a natural feel. These penetrating sealers are available in clear or tinted forms and some contain protective UV blockers or absorbers that slow the fading caused by sun exposure. Even liberally and evenly-applied coats of clear sealers require annual reapplications to maintain their color-enhancing and water-shedding capabilities.
Polyurethane meant for exterior use can give a cedar swing set a more finished appearance and is able to last for years, depending on the wear and weathering the swing set receives. Sand the cedar wood with 180 grit sandpaper and apply either a water or oil-based polyurethane in two or three coats over a few days. If the swing set is kept in full sun, polyurethane may not be the most suitable finish option, as it tends to wear and require frequent removal and reapplication under these conditions.
Spar Varnish or Spar Urethane
Spar varnish gives outdoor surfaces a clear and flexible protective layer that does not delaminate with sun exposure like polyurethane does. Spar varnish wears slowly, becoming cloudy after a few years. Simply sand the surface lightly, remove any mildew or dirt and add another coat of spar varnish when this occurs. Spar urethane is another clear coating option that offers the same UV stability as spar varnish.
Opaque Finish Options
Although many owners of cedar wood furniture likely prefer to seal and protect their furniture with a clear finish that will show off the wood's characteristics, opaque and semi-opaque finishes can hide problems with the wood's appearance on an older swing set and can withstand weathering better than clear finishes, making them more long-lasting. Latex or acrylic stain or exterior paint are all opaque finish options.
Leaving Cedar Untreated
Cedar wood can generally perform quite well even with no finish. The wood ages to become a silvery-gray and has a rustic feel. Rather than apply a finish, simply sand the wood and wash the furniture annually. Clean the wood using a mild detergent solution and a non-wire brush and then, if mildew is present, treat it with a mildew wash or bleach solution.