Woodworking FAQ: Clear Finishes
Q: If I stain a piece of furniture, do I have to apply a finish like varnish or lacquer?
A: If you don’t apply some kind of sealer the wood will be dried-out and lifeless. Stain and a finish are two entirely different things.
A stain is intended to darken or color wood by adding pigments, but stain does not protect the wood. When you rub stain into wood, it brings out the grain pattern and gives the wood a more dramatic look.
The final step in staining wood is to wipe off any excess, so the process leaves nothing behind.
A finish is typically applied after a piece has already been stained and is normally applied with a paintbrush.
When the finish dries it imparts a protective coating that adds luster, protects the wood from spills and scratches, and prevents the wood from drying out.
Q: What is the best finish to put on hardwood floors?
A: Of all the wood in your home, hardwood floors take the most abuse. You'll want to use a strong finish on them to protect them from spills, scratches and abrasion from foot traffic, especially when there is dirt or grit present on the surface. Polyurethane finishes provide the kind of hard, durable finish that wood floors require.
Polyurethane is easy to apply, but be sure to use a natural bristle brush rather than a foam pad. A foam pad will leave tiny air bubbles in the finish.
When applying polyurethane finish, allow the first coat to dry overnight, then sand it lightly with 220-grit sandpaper. Always apply a second coat, and you may want to repeat the process with a third coat. Most floors require two to three coats of polyurethane for adequate protection.
Q: Can you recommend a finish that's easy to apply?
A: A versatile and easy-to-apply finish is tung oil, and it's been used for centuries to beautify and protect wood. To apply tung oil, simply pour a small amount into a shallow container and apply it with a brush, rag or foam pad.
Apply tung oil liberally, then wipe off the excess with a clean rag. Tung oil provides a rich, beautiful finish that may darken the wood, but unlike stains tung oil penetrates and hardens within the wood to offer protection.
The only disadvantage of using it is that, since it is very thin, tung oil must be applied in multiple coats to be effective. About 3 coats of tung oil are required to offer the same amount of protection as a single coat of polyurethane. The good news is that tung oil is so easy to use and dries so quickly, you can apply several coats in a day. With polyurethane, you'll generally need to wait a day between coats.