Finishes are like superheros, they have core strengths and weaknesses, but no finish possesses every ability. All finishes are nontoxic when fully cured.
OILSLinseed Oil: Warm glow that darkens with age. Fairly durable, Easily applied with rags, wiping off excess. Takes relatively long time to dry and needs sanding on each layer. Raw Linseed oil is rarely used for wood as it takes too long to dry. Heat-treated and polymerized oils dry faster.
Tung Oil: Lighter in colour, faster to dry and water-resistant.
Protection: Very Little.
WAXESUsually not a finish in itself, but a polish used after laquers or shellacs. Creates shine Short term and needs frequent re-application. Easily applied that needs sanding between coats. Can easily be removed with solvents. Needs to be buffed.
Protection: Short Term.
BLENDSMixtures of oil with some varnish added, offer some of the best attributes of both ingredients: the easy application of true oils and the protective qualities of varnish. Oil and varnish blends will dry a bit harder than true oils, and the finishes will build quicker, dry faster and with fewer applications. Easily applied with rags.
Protection: Low, but more than pure oils.
SHELLACSShellac is available premixed or in flake form that you can mix it yourself with denatured alcohol. The premixed variety is available in orange (amber) and clear, which is shellac that's been bleached. With the flakes, shellac is available in a wider variety of colors. The wax in shellac decreases the finish's resistance to water and prevents some finishes from bonding to it.
French polishing is a famous finishing method of applying many thin coats of shellac using a rubbing pad, yielding a very fine glossy finish.
Protection: Fair against water, good on solvents except alcohol.
LAQUERSRegarded as the best all-around finish for wood because it dries fast, imparts an incredible depth and richness to the wood, exhibits moderate to excellent durability and rubs out well.
Nitrocellulose lacquer is the most common. This type of lacquer has moderate water resistance, but it's sensitive to heat and certain solvents. The biggest drawback is the finish's tendency to yellow as it ages, which shows clearly on light-colored woods.
Acrylic-modified lacquer possesses the same general properties of nitrocellulose lacquer, except it is absolutely water-white, meaning it will not show as an amber color when applied over light-colored woods. Also, the finish won't turn yellow over time.
Catalyzed lacquer bridges the gap between the application traits of nitrocellulose lacquer and the durability of varnish.
Protection: Decent, Soft finish.
VARNISHESMade of tough and durable synthetic resins modified with drying oils. Resins make this finish more durable than oil and surpass most other finishes in resistance to water, heat, solvents and other chemicals. Typically applied with a brush, although 'wiping varnish' can be applied with a rag. Can be stripped using paint removers. Alkyd varnish has a yellow/organge tint. It is the standard all-purpose with decent protective qualities. Phenolic varnish is predominantly for exterior use. Urethane varnish also called polyurethane can look like plastic with many coats. It offers better resistance to heat, solvents and abrasions than any other varnish.
WATER-BASEDTransparent. Newer products (2009) are UV stable. Durable after approx. 10 day curing period Safer than oil-based, fewer volatile organic compounds. Applied with Brush or spray. Fast drying demands care in application techniques. Can be stripped using paint removers.
EPOXYThick, high-gloss, and transparent. Some formulations can cloud or yellow with UV exposure. Flexible and durable. Easy pour-on application for flat surfaces, difficult to apply evenly on more complicated shapes. Cleanable with acetone when liquid, Irreversible once cured.