Sanding is an important step in any woodworking job because it helps you to remove the wood’s defects and create a smooth surface that looks far better than a non-sanded one. If you want proper bonding when applying coats of paint, you should sand them in between.
Sanding between coats of paint is only suggested with water-based stains. Other forms of wood stains, on the other hand, merely require sanding the surface before applying the first coat of paint.
Why should you sand between coats of paint?
Sanding between coats of paint will help you create a smooth finish that is less likely to show brush strokes or other imperfections.
With sanding, you can hide down all those rough edges, remove dried-on dirt and grime, and even out the surface before painting it. These imperfections may be difficult to notice with the naked eye but will stand out like a sore thumb once stained. In the end, you will create a smoother surface that traps less dirt, making it easier to keep clean.
TIP: Sanding before spraying with primer isn't necessary unless you're going to be painting over an extremely dirty or rough surface that needs to be leveled out.
How do you sand between coats of paint?
The best method for sanding is to use a power sander with low-grit sandpaper.
Here are a few sanding tips to make things easier for you:
- Use long, even strokes over the surface in one direction only – Using circular or random motions can cause uneven surfaces that may not lie flat when dried.
- Sand across the grain of the wood, not with it – If you sand against the grain of a board, you will make scratches that show up in your new paint job and won’t be going away anytime soon!
- Use furniture-grade sandpaper – If you’re working with different types of wood or on a large area, you may want to invest in some high-quality sandpaper that won’t wear out as fast as the cheap stuff.
- Avoid sanding over any joints – When sanding close to a joint, you run the risk of raising it above the level of the surrounding wood.
- Don’t forget to wear a mask and safety goggles when sanding – paint contains chemicals that can irritate your skin and eyes.
How Long Should Stain Dry Before Sanding?
You should wait at least a few hours for the stain to dry before sanding. This will depend on the humidity levels in your area and the type of stain. If you live in a hot, dry environment, it may take longer for water-based stains to dry than if you live in a humid area.
In general, when using water-based stains, wait at least two hours between coats for the surface to dry completely or until it no longer feels tacky to the touch. When using oil-based stains, wait at least five hours before sanding between coats of paint.
TIP: Every type of stain has a different drying time, so be sure to read the instructions carefully before you apply your first coat of stain.
The best way is to Use a Sprayer
Stains applied with a sprayer will dry faster than those applied by a roller and will require a lot less sanding at the end.
Here are some benefits:
- You will save time
- You will use less paint
- Your painted surface will be more even
- It will be easier to achieve a consistent finish
- The stains dry much faster, thus allowing you to paint 2 coats in a single day
- There will be fewer sags
- Your paint job will stand out better and look more professional
CONCLUSION: Even If you don't have a lot of wood to paint, it is well worth the effort of investing in a inexpensive sprayer like the one above.
Types of Stains available
It depends on the sort of stain you’re using whether sanding between coats is necessary or not, as certain stain types are more prone to developing defects.
Water-based stains are the most popular and widely available forms of stain. They dry quickly and can be applied with a cloth or sprayer. They are best used on natural or stained woods, but can also be applied over paint.
These stains can create grain raising, which is the swelling of wood fibers as a result of contact with water. It is preferred to be sanded between coats of paint to ensure a smooth finish.
Oil-based stains are less common than water-based stains but provide a smoother finish and deeper color. They are less absorbent of the wood’s natural color and will camouflage more imperfections.
Oil stain will penetrate the pores in your wooden surface, leaving a smooth finish with rich, even color saturation. Using them will add a sharp, bold color to your wooden surface.
Sanding between coats of oil-based stain is optional. After you apply the first coat of stain, whether you sand between coats or not will depend on the look you’re going for. If you feel the finish is not smooth enough then you can apply a few more coats and sand between them.
Gel stains are oil-based stains that have a thicker consistency than regular oil-based stains, which may make it easier to apply with a cloth. Gel stains penetrate deeper than liquid stains and provide more even color tones.
Sanding between coats of gel stains is not required as it is often applied with a roller and will dry evenly. You should sand your surface before applying your first coat of any stain.
Lacquer stains are extremely fine-grained and have a smooth finish that can’t be achieved with water-based stains. They are thinner than other types of wood stains, so they penetrate deep into the pores in your wooden surface producing an even color tone with minimal grain showing through.
Lacquer Stain does not require sanding in between coats. It’s because it’s capable of melting through the lacquer’s second layer. You won’t have to worry about adhesion as a result.
Polyurethane stains are available in both water-based and oil-based forms. This type of wood stain works like lacquer. It penetrates the surface to produce rich colors with minimal grain showing through, but it also protects your wooden surface from outdoor elements.
No sanding is required between applications of Polyurethane Stain.
TIP: You might like my post: Can You Paint Over Polyurethane?
Metal-Complex Dye Stain
Metal-Complex Water-based dye stains don’t need to be sanded between applications and can be applied on a variety of surfaces. Because metals like copper and chromium are added to make the color more resistant to fading, they are the most durable of stains and can be used outside.
Water-Soluble Dye Stain
This type of wood stain is the only type that provides an opaque color finish with a matte appearance. It penetrates the surface to produce rich colors with minimal grain showing through, but it also protects your wooden surface from outdoor elements.
You can either lightly sand it between coats or not at all. It mainly depends on the look you’re going for.
What Grit Sandpaper should you use for Stained Wood?
Different types of sandpaper are used for different tasks. Generally speaking, the finer the grit or number (i.e., 60 or above), the smoother and more even the surface. Sanding with very fine sandpaper, such as 220 grit, is recommended. Use 100-grit sandpaper and higher for staining and extra-fine sandpaper with a grain of 360 to 400 to finish surfaces smoothly.
Do You Need to Sand Stained Wood Before Applying Polyurethane?
Yes, always. You can use a piece of sandpaper to smooth out the surface of your stained wood with a minimum of 220-grit sandpaper after you’ve finished staining an item. If possible, it’s recommended that you wait at least three days before applying polyurethane.
When should you not sand between coats of paint?
It’s best not to sand between coats on pieces that will receive a stain or on pieces that already have a smooth surface. Also, if you’re working with unstable wood, such as spruce pine fir, it’s best not to sand at all because the dust from the wood is likely to cause respiratory problems.
What happens if you don't sand before painting?
If you don’t sand between coats, the new topcoat will unevenly bond to the previous coat. The last layer applied may stick differently than what is underneath it, causing bubbling and blistering. Sanding helps bring the layers of paint together evenly with each application, which means your finish will be smoother and more even.
When should you sand between coats of paint?
You need to sand between coats of paint when the previous coat has dried adequately but is still slightly rough or tacky. If the previous coat dries too hard, you may end up removing too much paint and creating a rough surface that will need re-sanding before you can apply the next layer of paint.