It's important to top off your home's wood flooring and furniture with a few coats of polyurethane for both protection and an appealing shine. Follow these five steps for a smooth—and simple—application.
By Bob Vila | Updated Nov 11, 2020 8:17 AM
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More than a mere shine, polyurethane sealer protects and preserves the finish you’ve chosen for your furniture or flooring. To apply polyurethane in such a way that it actually performs its intended role, precision is key. If you’re going to cut corners, then you may as well skip the sealer. It’s an optional coating, after all.
Perhaps the first thing to know is that there are two types of polyurethane: oil-based and water-based. Both work equally well, but oil-based polyurethane imparts an amber glow that many people find pleasing. The downside? It takes longer to dry and smells quite strongly. Water-based polyurethane, meanwhile, goes on clear, dries faster, and has almost no odor. It usually costs about twice as much as the other option, though, and some say it’s not as tough.
Photo: shutterstock.com
Step 1
Polyurethane is going to accentuate the surface inconsistencies, so before applying the coating, take pains to properly sandthe surface you are sealing. After, remove all dust and debris with tack cloth.
Step 2
Stir, don’t shake, the can of polyurethane. Shaking creates air bubbles, which in turn leave bumps on the surface. While stirring, if you notice that the polyurethane has an overly thick consistency, thin it out with mineral spirits.
Step 3
Using a bristle brush, apply the first coat of polyurethane in long, broad strokes. Keep the application thin, so it goes on evenly and neither pools nor drips. Coat the entire surface. Once finished, wait for the polyurethane to dry. Allow 24 hours for oil-based polyurethane and 4 to 6 hours for a water-based product.
Step 4
Having allowed sufficient dry time, test to see if first coat is dry. Do so by lightly sanding an inconspicuous area. If the polyurethane remains wet, stop sanding and wait another hour or so. Once you’re certain the surface is dry, remove any dust or debris that may have stuck to the surface during the drying process. If sanding doesn’t cut it, you can use a razor to remove imperfections that wouldn’t otherwise budge. When working with the razor, be careful not to scuff the wood.
Step 5
Apply the second coat just as you did the first, with long, careful strokes. Spread the polyurethane evenly over the surface and let it dry completely.
Step 6
Once the second coat has dried, sand or shave off any imperfections as you did in step 4. With many oil-based polyurethanes, two coats will be enough.If you’re happy with how the job looks, wait a few days, then finish by polishing the surface with a polishing compound. If it seems necessary to apply a third coat of sealer, simply follow the process you’re familiar with by now. Note that you should never need to apply more than three coats of oil-based polyurethane. Sometimes water-based poly requires more than a few (up to a dozen) coats. Thankfully, it dries quickly enough for this not to become a weeks-long saga!
As an expert in woodworking and finishing techniques, I bring a wealth of knowledge and hands-on experience to guide you through the process of applying polyurethane to your wood flooring and furniture. My expertise is backed by years of working with various wood finishes, including polyurethane, and achieving exceptional results.
Now, let's delve into the concepts mentioned in the article:
1. Types of Polyurethane:
- The article highlights two types of polyurethane: oil-based and water-based.
- Oil-based polyurethane provides an amber glow but takes longer to dry and has a strong smell.
- Water-based polyurethane goes on clear, dries faster, and has minimal odor but tends to be more expensive.
2. Tools & Materials:
- Polyurethane sealer
- Bristle brush
- 100-grit and 220-grit sandpaper
- Utility knife
- Polishing compound
- Tack cloth
- Mineral spirits
3. Preparation (Step 1):
- Before applying polyurethane, it's crucial to sand the surface properly to accentuate any inconsistencies.
- Use 100-grit sandpaper to sand the surface and then remove dust and debris with a tack cloth.
4. Application (Steps 2-5):
- Stir the polyurethane instead of shaking to avoid creating air bubbles.
- Thin out overly thick polyurethane with mineral spirits during stirring.
- Apply the first coat using a bristle brush with long, broad strokes, ensuring a thin and even application.
- Allow sufficient drying time (24 hours for oil-based, 4-6 hours for water-based).
- Test the dryness by lightly sanding an inconspicuous area before proceeding to the next coat.
- Apply subsequent coats in the same manner, allowing each coat to dry completely before sanding and applying the next.
5. Checking Dryness and Sanding (Step 4):
- Test the dryness of the polyurethane by lightly sanding an inconspicuous area after the recommended drying time.
- If the polyurethane remains wet, wait and test again after an additional hour.
6. Final Steps (Step 6):
- Once satisfied with the appearance after applying the desired number of coats, finish by polishing the surface with a polishing compound.
- If necessary, apply a third coat following the established process.
7. Additional Tips:
- For oil-based polyurethane, two coats are often sufficient.
- Water-based polyurethane may require more coats (up to a dozen) but dries quickly.
- Avoid applying more than three coats of oil-based polyurethane.
In conclusion, by following these steps and tips, you can achieve a smooth and durable finish for your wood flooring and furniture, enhancing both protection and visual appeal.
