Everything you need to know about finishes

Hey there, time traveller!
This article was published 27/08/2006 (7026 days ago), so information in it may no longer be current.

THE finishes on the market have come a long way. Your lifestyle and specific needs will dictate the best products for your home.

1. The following tricks will help you determine what type of finish is currently on a floor or furniture piece. If the wood was installed or built before 1965, you can assume the finish used was varnish or shellac. Using a coin scratch the surface in an inconspicuous area. If the finish flakes, it is likely shellac or varnish. Also, moisten a rag with denatured alcohol and rub on a hidden area. If the finish turns gummy it is shellac. Next check for wax finish. In an inconspicuous area, apply two drops of water. If within 10 minutes white spots appear, the floor has a wax finish. To remove the white spots, rub with a fine steel wool dampened with wax. If the floor does not scratch and no watermarks appear, the area has a surface finish and should be maintained accordingly.

2. Shellac is an organic, natural finish. It is created using the excrement of the lac bug combined with denatured alcohol. Shellac is susceptible to water spotting, so therefore is not recommended on kitchen or bathroom floors. Shellac is an excellent barrier to protect wood from humidity. Shellac and varnishes are used much less than in the past because they require full sanding before application.

3. The difference between lacquer and shellac. Lacquer is a man-made finish, developed after the First World War. It is usually applied with a spray gun and is widely used on furniture, but may strip paint. It is best to apply lacquer over another kind of clear coat or paint. Shellac is more flexible and less hard than lacquer and can be brushed or sprayed on. Consider cold-cure lacquer if you want a very glossy black or white finish. Note: Shellac is the only FDA approved finish for children’s toys.

4. The difference between varnish and shellac. Varnish is harder than shellac making touch-ups more difficult. Varnish can be brushed several times during application while shellac dries faster and has a tendency to lap mark and dribble (meaning application must be fast). Shellac repair is easier than varnish but both are equally strong. Varnish is not as durable as some of the newer finishes. Use three coats, leaving each coat to dry overnight with light sanding and vacuuming between coats.

5. Linseed oil, oil varnishes and some urethanes react with air to produce a film finish that is more durable than shellac. This finish is strong, making it difficult for water and chemicals to penetrate.

6. Good quality urethane has UV blockers (check the label). As well, good quality water-based urethanes do not yellow (apply four coats). This finish is durable, has a mild odour, is fast drying, non-combustible, available in satin to gloss finish. Disadvantages: water-based urethane is typically more expensive than oil and the finish is not as thick looking. Urethane appears milky but goes on clear.

Tip: Read the label for recommended use and make sure the product says “Non-Yellowing”!

7. Polyurethane oil-based finishes are moisture resistant and one of the most scratch resistant products today. Polyurethane is durable, has a moderate odour, is slow to dry and combustible, it is hard to touch-up and may darken the wood with age, available in satin to gloss finish. Apply three coats, leaving each coat to dry overnight with light sanding and vacuuming between coats.

8. The words polyurethane and urethane are interchangeable. The term polyurethane came about in the past because the predominant chemical group present in the polymer was the urethane group. Polyurethane products are durable, non-marking, oil, solvent, mould, fungus and water-resistant.

Tip: A solvent-based urethane has oil components that are used as part of the chemical makeup of the polyurethane finish. Dry time is 24 hours.

9. Wax or oil finishes are durable, shiny, have a mild odour, are combustible and may leave water spots.

Tip: Do not wax a urethane finished floor; doing so will cause the wood to become slippery, requiring continuous waxing as maintenance.

10. Add shine to old indoor wood furniture by applying a wax finish. Begin by sealing the wood with a clear varnish. Carnauba, Bri-wax and beeswax are good choices.

Caution: Using commercial wax or polishes can reduce the lustre of your finish and create a film, which will require extensive refinishing.

11. Before choosing a finish, decide whether the wood will be matte, satin or gloss. Exterior grade varnish has the best water resistance. Marine grade is designed to resist salt. Satin or semi gloss finishes show less traffic patterns than gloss.

Tip: Always apply any brush on finish with a very good quality brush.

12. Oil-based finishes bring out the natural colour of wood. Water-based finishes leaves the wood lighter than oil and has a tendency to reduce the natural colour variations of the grain.

13. There are a few different options for stripping wood surfaces: UV strippers, sanding and chemical strippers. If the floor has been sanded often it may be too thin to be sanded again. If this is the case, chemical removal is a good option (ventilation is important).

14. Tired of playing Solitaire? Use an old deck of cards to help remove an old finish. Apply solvent according to directions, when the solvent bubbles, scrape the area with one card after another instead of a sharp blade.

15. To refinish oak cabinets, rub with super-fine steel wool and contact cement solvent. Wash with all-purpose cleaner and apply two coats of urethane.

Tip: Remove grease on cupboards by applying car wax and buffing.

Solutions, is compiled from various sources, including: arslaniarestoration.com, woodflooronline.com, victorianparlorantiques.com, smbryx.com, polyprod.com, ehow.com, draculaconstruction.com. Similar information may be found elsewhere.

Reena Nerbas is the author of Household Solutions & Substitutions. She can be heard biweekly on the CBC radio show Up To Speed.

householdsolutions@mts.net