Oil-varnish blend, powerful potion for dull finishes
An oil-varnish blend, often referred to as Danish oil or antique oil finish, offers an effective means of hiding minor surface flaws and restoring sheen to dull finishes. And it's an easy fix, too: Just clean the surface (a spray-on household cleaner works fine), rub the finish on as shown in the photo, and then wipe off the excess. Rubbing off all the excess is the key to avoiding a smeary, sticky surface.
(Be careful with rags you use with oil-varnish; there's a danger of fire from spontaneous combustion. Spread the rags and hang them to dry evenly all over rather than wadding them up.)
In effect, going over an existing finish with an oil-varnish blend is similar to shining it up with paste wax. (See Paste wax, WOOD® magazine issue 112, page 14.) The difference is that an oil-varnish blend is more permanent. (You should wait about a year between reapplications. Unlike wax, oil-varnish will build up on the surface.) In many cases, an oil-varnish product can color deeply scarred spots.
This technique works well on legs, doors, drawer fronts, cabinet sides, skirts, panels, and other such furniture parts. It could prove less successful on tabletops, desktops, and other heavily used surfaces where the soft finish might not give enough abrasion resistance. You probably would be better off to shine up the surface with paste wax in these situations.
Mixing oil (often linseed or tung oil) with some varnish (polyurethane varnish, in some products) creates a finishing material with a blend of qualities. The varnish provides a higher gloss and offers more protection than oil alone. The oil in the mix slows curing--giving you more time for application--but makes the cured finish softer than varnish alone.
You probably won't find oil-varnish finish labeled as such in stores. It's usually billed as an oil finish; some popular brands are Deftoil Danish Oil Finish, Minwax Antique Oil Finish, Olympic Antique Oil Finish, and Watco Danish Oil Finish.
And don't expect the labeling to shed much light on which oil and varnish are in the mix, or in what proportions.
Photograph: Baldwin Photography