Polyurethane is a popular finish for various surfaces because it offers a durable, smooth, and glassy look. Unfortunately, applying and buffing polyurethane does not always work out as advertised. Most DIYers find that their polyurethane finishes need a more glossy aesthetic than they aimed for.
If your polyurethane finish has a bumpy, uneven, or dull appearance that does not meet your standards, do not throw in the towel. You do not have to sand away the entire finish and start over. Buffing is the answer to your predicament. This article will guide you in bringing your polyurethane project to the next level.
Read on to discover more about:
- How to buff a polyurethane finish
- How to achieve a glossy finish
- How to achieve a satiny finish
- Mistake to avoid when applying and buffing polyurethane
How to Buff a Polyurethane Finish
Buffing your polyurethane surface is much easier than you’d imagine.
1. Ensure your polyurethane finish is thick enough to withstand buffing.
If you attempt to buff a polyurethane finish that is not thick enough, you are likely to expose the bare wood. This does not mean that you should slather on thick coats of polyurethane to achieve a buffable finish.
When applying polyurethane with buffing in mind, ensure you apply no less than four thin coats. Standard wood finishing practice guides us to allow 24 hours of drying time between coats. It also calls for light sanding using 240-grit sandpaper before each coat. If you want to do it right, the four coats will take you four days before you can even think about buffing.
2. Prebuffing to even the surface
After methodically laying on your four layers of polyurethane, you are now ready to begin buffing your finish. If you look closely at the surface, you may notice small bumps. These bumps are created by dust that settles on your finish before it completely dries.
Prebuffing is the process of removing these bumps. Lightly sand the surface along the grain using old 240-grit sandpaper wrapped around a styrofoam block. . Using fresh sandpaper is not advisable as it buffs too aggressively. Used sandpaper is much gentler. Do not overdo the sanding.
Usually, a few light strokes are more than enough to get rid of the dust bumps. It will not take long for the surface to feel smoother. Prebuffing will cause the sheen to appear irregular because the sanded areas will appear duller than the rest of the surface. Do not stress over the uneven sheen, and the next steps will take care of this.
3. Spritz a thin layer of fine mist onto the polyurethane finish
Once your coats of polyurethane are completely dry, use a spray can to spritz cool water over the surface. Do not spray too much water on the finish. Aim to coat the entire surface with a thin mist. The thin mist will make your sanding-down efforts more efficient. Dry sanding is not recommended for polyurethane finishes.
4. Buffing using a handheld orbital sander
Next, you need a superfine 3M rubbing pad(or 2000 grit paper) and an orbital sander to buff the surface. The rubbing pad is better than sandpaper because its thick non-woven material creates a shinier finish. Fit the circular sandpaper sheet into the orbital sander. When purchasing sandpaper, read the labels carefully to avoid purchasing the dry instead of the wet use type.
Select the lowest power setting on the sander, then use slow horizontal motions to rub it across the surface. It is crucial that you use light and even pressure throughout the surface in order to get rid of all bumps and scratches on the surface.
Work methodically from one end of the surface to the other. If you want to achieve a perfect finish, consider having a bright light over the work surface. Angle the light to find areas that need a little more buffing. The orbital sander may have a tough time reaching some parts of the surface, e.g. curved areas. You can buff these areas by hand.
If you cannot find wet use sandpaper at your local home improvement store, try using a scrubbing pad instead. All you need to do is rest your sander’s surface on the scrubbing pad and select the lowest power setting. You can now use the technique described above. If you want a very shiny finish use a soft buffing pad instead of a scrubbing pad.
5. Wet sanding by hand
If you do not have or cannot rent an orbital sander, you can still achieve a perfect polyurethane finish by hand. You will need to purchase 1500-grit sandpaper. Use it to rub your polyurethane finish. Apply an even and small amount of pressure in long smooth motions until you cover the entire surface.
If you cannot find fine sandpaper, you can use lower grit level paper and wrap it around some styrofoam. A brown paper bag can be used instead of sandpaper if you are between a rock and a hard place.
6. Clean residue
As you buff your polyurethane, it is important to keep an eye out for dust or sludge building up on the surface. Whenever you notice the residue building up, wipe it off using a clean cloth. Allowing the residue to build on the surface will interfere with the buffing because it will clog your sandpaper or scrubbing pad’s surface.
7. Spray and buff repeatedly
Buffing polyurethane takes time. You will have to repeat the spraying and sanding until your polyurethane finish is rid of all the scratches and bumps. Apply less pressure when sanding on the edges and sides so you do not accidentally sand off the finish. If your scrubbing pad or sandpaper gets clogged with dust and debris, switch it out for a fresh one. The more you polish, the shinier your finish gets. Eventually, you will have a finish so smooth and shiny it might as well be glass.
Polishing to Get a Glossy Finish
If you want the type of glossy finish reserved for concert pianos and similarly grand items, you will need to polish the finish. Using your orbital sander and a foam buffing pad, apply a small amount of car polish onto the surface. Ensure you use clear polish. If you use the polish designed for dark surfaces, it will stain your polyurethane surface.
Buff the polish on your surface until it shines. Your surface may take a while to achieve the glossy look. Rub the surface in large circular motions to wipe away any excess polish. Finally, use a clean polishing cloth and swirl remover to remove any marks that may remain from the circular motions used to apply the polish.
Waxing to Get a Satin Finish
Using a polishing cloth or pad, rub a small amount of car wax onto the surface using short and smooth horizontal motions. Ensure you apply an even coat of wax to the entire surface. Begin by waxing the ends and edges of the surface to avoid messing up the surface if you wax them last.
Before the wax dries, use a paper shop towel to remove any excess wax. Try using long horizontal motions to ensure the surface of the polyurethane remains even. Finally, spray a light mist of water over the waxed surface and use a 0000 steel pad to lightly brush the surface.
Mistakes to Avoid When Applying and Buffing Polyurethane
Buffing polyurethane is a delicate task that requires the right tools and techniques to achieve the desired effect. Ensure you do not make these mistakes:
- Applying polyurethane before sanding the wooden surface – failure to properly sand and clean the surface will result in an uneven finish that causes some areas to appear darker than others
- Applying layers of polyurethane that are too thick – slathering on polyurethane will increase drying time and chances of polyurethane puddles forming.
- Not applying enough layers of polyurethane – if you apply less than three layers of polyurethane, you are much more likely to sand through the finish and expose the bare wood.
- Failure to allow enough drying time between coats will cause an uneven streaky finish.
- Failure to sand between coats will cause a rough and uneven finish.
Buffing polyurethane is the perfect way to finish your finish. This simple step will elevate your DIY project to the glossy mirror-like finishes on store-bought furniture. All you need to do is apply the polyurethane efficiently and gather all the necessary tools before you begin buffing. You should also avoid getting too aggressive with the buffing, especially when using an orbital sander, to avoid exposing the bare wood.
We hope this article proves useful in helping you achieve the polyurethane finish you desire.
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