How to Seal Wood: 13 Steps (with Pictures)

2024 Author: Samantha Chapman | [email protected]. Last modified: 2023-12-17 09:13

If you own a wooden cabinet and want to enhance the natural beauty of its grain instead of painting it, finishing it with a sealant can be a great way to highlight the surface and protect the wood. Before doing this, however, it is necessary to prepare the wood so that the sealant can adhere properly. The three most common insulators are polyurethane, shellac and lacquer; each has its own specific method of application.

Steps

Part 1 of 4: Prepare the Wood

Step 1. Sand the wood surface with sandpaper to make it smooth

Before applying the polyurethane, prepare the glass with a coat of sandpaper.

• Gradually switch from coarse to finer grain - this allows you to reduce the most noticeable surface irregularities before achieving the optimal finish.
• Gradually reduce the grain of the sandpaper until you achieve a satisfactory result.
• Sand along the grain of the wood (scraping back and forth) to avoid leaving marks on the surface.
• Wear a protective mask during the process to avoid inhaling the dust.

Step 2. Eliminate traces of dust to prevent it from mixing with the sealant

Use a dry cloth or one to remove dust from the wood.

Step 3. Avoid using water on untreated wood; it can alter the grain

Use a dry cloth to remove the dust before the absorbent one; being the latter more adherent and specific, it will eliminate even the most stubborn small dust particles

Step 4. If you intend to color the wood, do so before applying the sealant

It will no longer be possible to do this once treated.

• Generally, cloths are used to dye the wood.
• Spread the dye with a soaked tea towel and let it set.
• Then clean it by wiping it with a dry cloth.

Part 2 of 4: Polyurethane paint

Step 1. Apply the polyurethane to the wooden surface

Pour it on one end and gently spread it over the other parts.

• Wet a clean cloth with the polyurethane and distribute it evenly over the surface.
• Polyurethane is self-leveling; its consistency means that it spreads by itself on the surface, so you don't have to work too hard to get an even layer.

Step 2. Spread it over the surface

From long strokes with a cloth or a clean brush (a ready-to-use polyurethane-soaked cloth is the easiest method) to sprinkle the product.

• Make sure you apply an extra amount of polyurethane to the end (the one with the cut exposed) as it is the most absorbent part of the wood.
• Spread it from side to side, trying to distribute it gently on the surface evenly.

• Wear a pair of gloves during the process to protect your hands from stains and dirt.

  

Step 3. Apply more layers to achieve the result you want

Apply several layers of polyurethane to the surface you are working on; let each layer dry before applying the next.

• Be careful that it does not drip; be sure to sprinkle it well to prevent any irregularities in the finish.
• Use sandpaper between layers to smooth out uneven parts.
• Apply as many layers of polyurethane as you want until you get the desired result.
• Use the steel wool after the last finishing coat to polish and eliminate possible dust grains; do not do this if you are using a glossy polyurethane.
• Drying time varies, so be sure to carefully follow the instructions for the type of sealant you use. Also keep factors like humidity and temperature in mind.

Part 3 of 4: Shellac

Step 1. Soak the shellac sponge

Shellac is generally applied with a sponge to always have areas with soaked edges, in order to avoid overlapping between one coat and another if the paint should dry out.

Soak the sponge as much as possible before applying shellac

Step 2. Apply striped shellac

Make sure you keep the edges moist for each strip, quickly spreading it out on each side, one at a time.

• Start at one end and quickly spread the shellac along the surface, making sure it does not dry out during application.
• Applying this type of sealant is difficult, precisely because you always have to make sure that the hand just given remains moist when you move on to the next.

Step 3. Do not interfere with the drying phase

Shellac is different from polyurethane during this phase, so do not intervene in any way on the surface that has just been treated.

• Do not use steel wool.

  

• Do not sand between coats.

  

• Shellac blends with each new covering layer, creating a natural and homogeneous finish.

  

• If you are going to finish in another way, you can apply a new finish on the same shellac.

  

Part 4 of 4: Lacquer

Step 1. Know the product before applying it

Lacquer is a durable finishing product and is applied with a spray gun.

• The price of a spray gun varies between € 40 and € 90, depending on the model, and is required for application.
• The fact that it dries quickly makes lacquering a very difficult process, but the result is a high quality, strong and durable finish.
• It is not easy to apply it if you are not an expert, and it is not easy to remedy the possible mistakes you may make in the process.

Step 2. Apply the hairspray in thin layers to avoid the "orange peel" effect

Spray with the gun in very thin layers, always taking care to prevent the product from accumulating in a single point on the surface of the wood.

• Spray as you approach the piece, move the gun to aim it along the surface, aiming to cover about half of the previous track. Stop spraying once it has gone over the edges.

  

• When you spray the lacquer, quickly move the gun back and forth across the surface.

  

• Wait for the lacquer to dry between coats, and apply 3-4 coats in total.

  

• Do not dwell long on one spot with the gun to prevent excess sealant drops from creating the "orange peel" effect.

  

Step 3. Stay in a ventilated area and watch out for any sparks

Make sure you follow all safety precautions during the process.

• This sealant is highly toxic when inhaled, so make sure the area is well ventilated and use a respirator.
• Lacquer is also highly flammable, so proceed with extreme caution.
• If you use a fan to circulate the air in the workplace, make sure it does not create any spark.

Advice

• When sealing wood, the grain must be completely covered evenly to be protected from water infiltration and damage.
• Use specific cloths, particularly adherent to surfaces, to capture all traces of dust due to the sanding.
• Avoid rubbing a wet cloth on the raw wood to maintain the integrity of its grain.
• If you want to paint the piece, do not use sealant, but a primer. Using the primer assumes that you want to varnish the wood after passing it. You can also apply it by giving a single coat of product, using a spray gun or a brush.
• Always remember that the sandpaper must be rubbed in the direction of the wood grain.
• Give soft brush strokes, no matter which sealant you use.