You could fill a library with the different ways of finishing wood. There are oils and lacquers, urethanes and stains, sealers and varnishes. Some are wiped on, some are sprayed, while still others are brushed on. I could fill a book on just this subject alone so this post will be more of a primer to get you pointed in the right direction.
Finishing wood is as much of an art as it is a science. Each finish can come out completely different depending on a multitude of factors like the type of wood it is applied to, the ambient temperature and humidity, air flow or lack thereof, thickness of application, age of the finish.
Don’t be intimidated by all this. The best advice I can give you on the subject of finishing wood is to experiment. Get a piece of similar wood and try applying the treatment you are thinking about. If it doesn’t come out right, try tweaking your application and the conditions to see if you can make it work. If it’s beyond your abilities, then try a different technique.
Below is a list of the most typical types of wood finish used in old houses and some professional tips on how to work with each properly. Some are easier than others, so don’t get discouraged. There is a finish that will work for you!
Polyurethane (a type of varnish) is one of the most commonly used wood finishes today. It excels in high traffic areas like floors where it forms an incredibly hard and resilient coating that can handle just about anything. There are exterior versions of polyurethane call “spar varnish” which are a bit softer than their interior cousins. This softness allows them to remain flexible in the large temperature swings that occur outdoors. A regular polyurethane will crack and fail after a couple short years in brutal exterior settings, whereas a spar urethane can last a decade or so with care.
Polyurethane works best for floors though it also excels on doors and woodwork. The downside of this finish is that it leaves the wood feeling like it has a thick plastic coating on it. Good for hardwood floors that need the protection, but maybe not for furniture that you want to feel silky smooth. You can read more in my post All About Polyurethane.
- Ease of Application: Moderate
- Clean up and Thinning: Mineral Spirits or Paint Thinner
- Solvent: None (once cured, it cannot be removed except with sanding or scraping)
- Sheen: Available in Satin, Semi-Gloss, Gloss
- Recommended Application: Never shake the can, stir only to avoid bubbles in the finish. Apply 3 coats with a natural bristle brush or lamb’s wool pad (refer to manufacturer’s recommendations for drying times but usually leave about 12-24 hrs between coats) with light sanding between each coat. Sanding between coats provides for a smooth finish and is imperative for the successive coats to adhere to each other.
Laquer is a quick drying finish that is most typical on commercial furniture and cabinets today. Lacquer paints (essentially a tinted, opaque lacquer) are a typical finish for most cabinetry. Lacquer goes on in very thin coats and is almost exclusively sprayed on with HVLP (High Volume Low Pressure) sprayers since it dries so quickly. Without spraying, you’d be stuck with brush marks everywhere.
While it is hard for the amateur to work with lacquers, they do provide an incredibly beautiful and rich finish that is worth the extra work, especially if you are looking to put the finishing touches on a furniture project. Lacquers do have a tendency to yellow over the years, which makes them a bit less desirable for light colored woods.
- Easy of Application: Difficult
- Clean Up and Thinning: Lacquer Thinner
- Solvent: Lacquer Thinner (When applied to dried lacquer, Lacquer Thinner will dissolve the finish)
- Sheen: Matte, Low Satin, Satin, Semi-Gloss, High Gloss
- Recommended Application: Multiple coats, especially for clear coats (about 5 or 6 depending on the desired look). Coats dry and are sandable within an hour or two depending on conditions. Sand lightly between coats. Can be “rubbed out” to a silky smooth finish with high grit (400-800 grit) sandpaper.
Shellac is an old school finish common on woodwork in old houses. It is a relatively similar product in application to polyurethane, but instead of being made of petrochemicals, it is made from a naturally found resin from the lac bug. Flakes of this resin are dissolved in denatured alcohol and poof you have Shellac. This one of the oldest wood finishes whose history stretches into antiquity.
It is not quite as hard of a finish as oil based finishes like polyurethane and lacquer, but it is resilient enough for woodwork and trim. Floors are not a great place for this finish. One of the great things about Shellac is that is can be easily touched up without looking like it has been repaired. Applying new Shellac to a damaged area causes the old cured Shellac to re-emulsify (turn back into a liquid state). This great feature (along with the fact that Shellac doesn’t yellow over the years) allows Shellac touch ups to seamless blend in with the original finish.
Shellac was the wood finish of choice until being replaced by lacquer in the 1920s and 1930s.
- Ease of Application: Easy
- Clean Up and Thinning: Denatured Alcohol
- Solvent: Denatured Alcohol (When applied to dried Shellac, Denatured Alcohol will dissolve the finish)
- Sheen: Available in multiple sheens, depending on how much of the lac bug flakes are mixed into the denatured alcohol. The more flakes, the more matte the finish.
- Recommended Application: Easy to apply with a brush, pad, sprayer, or wiping cloth. Dries within minutes and can be recoated within 30-60 minutes. Multiple coats are recommended.
Before Shellac became extremely popular in the 19th century, wood finishes were mainly oil and wax. There are several different types of oil finishes available today. Tung Oil, Teak Oil, Antique Oil. All of these are a combination of different oils, resins and solvents to give them faster drying characteristics and more or less protective qualities. Most of these work great, but I prefer to go to the source, and for me that is Boiled Linseed Oil.
Boiled Linseed Oil is a slow-drying penetrating oil finish. Oil finishes like this, penetrate deeply into the wood and require multiple coats applied over several days. While an oil finish doesn’t really add a protective coating on the wood like the other finishes we’ve been discussing it does protect the wood in other ways.
Oil finishes penetrate deeply into the wood and slowly harden and strengthen the wood from within, which provides protection from water and other spills. Oil finishes also bring out a true richness in certain woods and since they don’t leave a coating on top of the wood, they give a feeling a nearness to the wood that is desirable in pieces that will be handled often. Oil finishes can also be given a beautiful sheen by rubbing them out with very fine sandpaper or 0000 steel wool.
- Ease of Application: Easy
- Clean Up and Thinning: Mineral Spirits or Paint Thinner
- Solvent: None
- Sheen: Usually a Satin sheen but the sheen can be altered by the amount it is rubbed out
- Recommended Application: Easiest to apply with a wiping cloth. Drying time can be days between coats depending on environmental conditions. Requires multiple coats until wood will no longer absorb anymore of the oil.
Popular around the same time as oil finishes, wax is best used as an addition to oil finishes. It provides minimal protection and should be reapplied occasionally to maintain its effectiveness. It’s fine when used in this way, but not recommended as a finish in and of itself.
You can read my earlier post on how to make this simple but effective finish at home. This finish really combines the best of both worlds. It gives you the deep penetrating protection of an oil finish with the protective coating of a varnish. Anything that is remarkably easy to use and effective will always keep a prominent place in my shop and this one is my go to finish for woodwork and antique furniture.
I use a 3 part mix of Boiled Linseed Oil, Polyurethane and Mineral Spirits. I can tailor this mixture to the needs of the project and often begin with a mix that is higher in Boiled Linseed Oil so that it can really penetrate the wood. Then slowly as I build up coats I switch to a mix that is heavier in Polyurethane.
- Ease of Application: Very Easy
- Clean Up and Thinning: Mineral Spirits or Paint Thinner
- Solvent: None
- Sheen: The sheen is dependent on the sheen of the polyurethane you use in your mix. Also, more coats provides more sheen. One or two coats usually leaves you with a matte finish.
- Recommended Application: Easiest to apply with a wiping cloth. Wipe on and let sit for about 20 mins so that the finish can soak into the wood. Wipe off any excess and let dry. Drying time can be days between coats depending on environmental conditions. Requires multiple coats to achieve an even finish. Sand moderately with 000 or 0000 steel wool between coats.
In recent years water based finishes like polycrylic and oil-modified polycrylics have been coming on the scene. These finishes, while they have come a long way since their introduction, are not quite ready for primetime if you ask me. While the clean up on these finishes is incredibly easy (wash and go), they do not provide the beauty and long lasting protection that oil-based finishes do.
I have no doubt that they will someday take over the market just as latex paint has pushed oil-based paint to the fringes of the painting industry. But that time has yet come.
Hopefully this has given you enough info to decide which wood finish is for you. There are so many options available to you for your old house that choosing the right finish may be the hardest part.
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I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.