You’ve completed the woodworking portion of your project and now comes an important decision; how to finish it. One thing is certain; if you make a bad choice, or do a “rush job” on this step, it can negate all of the great work that you’ve done up to this point.
In this article I’ll share some decision criteria to help you choose the right products and approach.
Sanding First
Before taking any actual finishing steps it will be important to understand that, regardless of your finish product and process, the best finish cannot overcome a poor sanding job.
So, take your time, sand carefully through each grit in your sequence (I usually start with 80 grit and go through 320 or 400, but that varies depending on the project), and carefully inspect your project before applying the first coat of finish to ensure that all of the sanding marks and glue spots are removed.
To choose the right finish for your project I suggest considering the following questions:
Will your project come in contact with food?
If your project will have contact with food, such as a cutting board, salad bowl or charcuterie board, you will have to take this into consideration.
Most modern finishes are considered to be food safe after the finish cures, which is generally about 30 days after application depending on temperature and humidity conditions.
If a project will be used prior to cure time, or if you want to increase your confidence around food safety, there are products that are considered to be food safe immediately, such as mineral oil and walnut oil.
Will the project live indoors or outdoors?
The requirements for outdoor finishes are much different than indoor finishes. Depending on where you live, your piece might be exposed to extreme swings in temperature, humidity, moisture and intense sun.
You’ll want to make your decision on finish based on what you need to protect against, as well as how much maintenance you want to sign up for.
Top coats such as Spar Varnish look great, and provide some protection against moisture and sun (although not nearly as much protection as you might assume).
If you apply a top coat finish, you will have a great looking project as long as you re-apply the finish every single year. And reapplying a top-coat finish means a lot of prep work in the form of sanding and scraping.
Penetrating finishes look great and repel moisture for a year, and generally look ok for another year after that, so applying every other year is generally adequate. If you stick with clear finishes your re-application will be pretty easy, with a light sanding and easy application.
If you prefer a tinted finish, you might decide that you need to apply every year, or suffer with a fading/spotty finish on your off years.
Will the piece be exposed regularly to moisture and abrasion resistance?
If your goal is to keep moisture and abrasion from wearing out the finish, you will want to use a top coat such as poly urethane or catalyzed lacquer.
If you build enough coats those finishes will prevent moisture damage from casual exposure, and will minimize the effects of ongoing incidental contact from people and household objects.
Do you prefer to spray, wipe, or brush your finishes?
Some people prefer to spray their finishes, and if you invest the time to get the hang of this, the results can be remarkable. Even rattle can spray finishes can produce a fantastic finish.
Brushing a finish can be challenging, but good results can be achieved if you use good materials and follow the application instructions. Wipe on finishes are kid-simple and can achieve great results if you are patient.
They are generally thinner than brush-on finishes so they require more coats, but for someone who builds a small number of projects for their family or friends each year, wipe-on finishes are a great way to go.
Do you want to enhance or preserve natural wood color?
Most finishes will darken the tone and enhance the grain of a wood project. If that is desirable to you, most options will work for you. Some projects call for preservation of natural color; you want it to be protected but not modified.
In those cases you will want to consider water based top-coat finishes. My go-to product for that application is Minwax Polycrylic, as it has virtually no impact on wood color or tone.
Do you plan to repair minor dings in the finish?
If repairability is important, consider using penetrating finishes such as Danish Oil or Tung Oil, because you can always add another coat without much preparation.
If you want a repairable topcoat, avoid polyurethane and focus instead on lacquer or shellac, as these are more conducive to spot repair (as opposed to refinishing and entire surface to fix one small spot).
Outdoor Projects:
For projects that will live outdoors, I prefer to use clear deck finish. The better, longer-lasting products can be found at a good paint store such as Sherwin Williams, or your local point store.
Other products work, but after a few years I get tired of maintaining exterior top-coats and tinted products that look shotty after one year of exposure.
Food contact projects:
I generally use mineral oil, butcher-block finish or salad bowl finish when a project will have frequent food contact.
Furniture and accessories:
If a project will be used as an accent piece and not exposed to much moisture and abrasion, I like to use clear penetrating oils such as Tung Oil, as a hand-rubbed oil finish can add warmth and instant patina to a piece better than other options.
Penetrating oil finishes offer virtually no protection, however, so if a durable top coat is required, I generally use a combination of wipe-on poly on the entire project, with a few additional coats of rattle-can poly on the top surface.
If I were to scale up the volume of furniture that I make, I would invest in a good system to spray lacquer, as this offers a fast, efficient way to quickly build up a beautiful, durable finish.
