How Many Coats of Boiled Linseed Oil? (Different Surfaces)

To make boiled linseed oil lighter, the finish must be exposed to dries and hot air. But, how many coats of boiled linseed oil do you need?

You must apply 3 light coats of boiled linseed oil. The first coat absorbs into the wood and forms a substrate layer. The next two coats aren’t absorbed as much but stay on top of the surface where the finish becomes hard. 

While 3 coats of boiled linseed oil is the standard, you might need fewer or more coats depending on the brand of linseed oil, surface type, and the finish type you want. 

This post reveals a lot more about the number of boiled linseed oil coats required for different interior and exterior surfaces. Let’s dive in.

Maximum and Minimum Coats of Boiled Linseed Oil

Maximum and Minimum Coats of Boiled Linseed Oil

Maximum

The maximum number of coats of boiled linseed oil is 4. You shouldn’t apply more than 4 coats of boiled linseed oil. It’s recommended to apply only 3 coats of boiled linseed oil, but if you are working with porous hardwood, you can apply 4 coats.

If you apply 5 coats of boiled linseed oil it will become difficult to control and protect the finish from contaminants while it dries. The finish will take longer to dry, you must wait longer for each coat to dry before applying the next one, and the finish can turn sticky. 

Boiled linseed oil penetrates wood deeply when applied. The first, and in some cases second coat of boiled linseed oil, is absorbed deep into the wood fibers. When the wood has absorbed as much boiled linseed oil as it can, the absorbed oil dries to form the substrate layer. Then you must apply 1-2 coats to form the top coat. This is why 4 coats of boiled linseed oil is the maximum. 

If you use too many coats of boiled linseed oil, the finish will take very long to dry. This is because there will be too much linseed oil on the wood than can be absorbed. In extreme cases, the boiled linseed oil will not dry and will turn sticky. When this happens, dust nibs and filth will settle on the sticky boiled linseed oil making it turn dark.

Minimum

The minimum number of coats for boiled linseed oil is 2. That’s because the first coat of boiled linseed oil will be absorbed into the wood, so you need another coat to form a layer over the wood. 

If you apply only 1 coat of boiled linseed oil, the finish will be weak and will have a light color shade. That’s because there wouldn’t be enough boiled linseed oil over the surface to protect the wood from moisture or other types of wood damage. 

Boiled linseed oil has a thin flow because the wood oil is thinned with oil-based solvents like mineral spirits and turpentine. Since the boiled linseed oil is thin, the first coat automatically soaks in the wood when applied. So, you need a second coat to cover the surface and provide protection. This is why two coats of boiled linseed oil is the minimum. 

However, you can apply only 1 coat if you use raw linseed oil. That’s because raw linseed oil is thicker and offers more coverage. 

Should You Apply an Extra Coat of Boiled Linseed Oil?

To know if you need another coat of boiled linseed oil, touch the texture of the finish with your fingers after the finish has dried. If you can feel the wood grain with your finger, it means the wood oil was absorbed by the wood and it didn’t cover the wood. So, you need another coat or two. 

If you can’t feel the wood grain while touching the wood, it means the boiled linseed oil has formed a layer over the wood and will protect it. If this is the case, you don’t need an extra coating. However, you can apply one more coat to deepen the finish color. 

You can also use the water test to know if you need another coat of boiled linseed oil. Sprinkle some water over the surface and wait a few minutes. If the wood absorbs the water, you need another coat of boiled linseed oil. If the wood doesn’t absorb the water, you don’t need another coat. However, this test should be done after the wool oil has dried. When you have enough coats of boiled linseed oil, the finish will become water-resistant.

You can check the manufacturer’s instructions to know exactly how many coats you must apply. Manufacturers often recommend the number of boiled linseed oil coats needed for different types of materials and surfaces. So, check the bottle of the wood oil, or the manual (if it comes with one). 

Dry Time Between Coats of Boiled Linseed Oil 

Dry Time Between Coats of Boiled Linseed Oil 

You must wait 6 hours between coats of boiled linseed oil. That’s because boiled linseed oil takes 6-12 hours to dry enough for a re-coat.

However, the dry time depends on the porosity of the surface, the drying conditions, and the brand of the boiled linseed oil. So, the re-coat time can be more or less than 6 hours. 

Boiled linseed oil dries to touch within 1 hour, but you must let it dry for a few more hours before re-coating. If you re-coat too soon, you will ruin the finish. To know for sure how long to wait between coats, check the manufacturer’s instructions.

Sanding Between Coats of Linseed Oil

Sanding Between Coats of Linseed Oil

You don’t have to sand between coats of boiled linseed oil. That’s because the second coat of boiled linseed oil sticks to the first coat without sanding. Also, boiled linseed oil doesn’t form a thick glossy finish that repels moisture, so the next coat sticks easier. 

However, you can sand between coats to help the wood oil stick better and get a perfect finish. When you sand between coats, you improve the adhesion between the coats of boiled linseed oil. Since the coats adhere better, the finish will be stronger and smoother. 

Sanding helps to remove dust, debris, and grain that sits on the layer of the boiled linseed oil while drying. If you don’t remove the dirt, the finish will be riddled with bumps and might peel off. 

To sand between coats of boiled linseed oil, you must use 400-grit sandpaper or 0000-grade steel wire. These two tools will polish and buff the finish but won’t remove it. However, you shouldn’t use coarse or medium-grit sandpaper as these grits are too harsh and might remove the wood oil. 

Different Surfaces

Wood

You must apply 3-4 coats of boiled linseed oil on the hardwood. But, for softwood, you only need 2 coats. 

Hardwood is more porous and accepts wood oil evenly. On the other hand, softwood doesn’t accept wood oil evenly, so you need a wood conditioner or a sanding sealer before applying boiled linseed oil. 

Cedar

Cedar is a softwood so you need 2 coats of boiled linseed oil for a start. After applying two coats of the boiled linseed oil to cedar, check the wood surface to see if an extra coat is needed.

However, you must apply a coat of wood condition on cedar wood before applying boiled linseed oil. This helps the cedar wood absorb the wood oil evenly. 

Worktop

For worktops such as tabletops, workbenches, or countertops, you need 3 light coats of boiled linseed oil. However, you can apply 4 coats if the wood is very porous. 

Worktops experience a lot of usage, stain, and friction so you need more coats of boiled linseed oil to offer more protection to the wood. 

Outdoor Furniture

For outdoor furniture, you need 4 coats of boiled linseed oil. That’s because exterior furniture is exposed to dust, stains, moisture, and UV rays, so you need more coats. 

If you don’t use enough coats of boiled linseed oil on outdoor furniture, the finish will get removed from the surface and expose the wood to the harsh exterior environment. 

You should know that boiled linseed oil is recommended for interior applications and not for outdoor furniture. If you want to use boiled linseed oil on outdoor furniture, pick the brand that is designed for outdoor use.

Final Words

The number of boiled linseed oil coats depends on the surface type and the brand type. However, the maximum number of coats you must apply is 4, while the minimum is 2 coats of boiled linseed oil. 3 coats is the recommended amount of coats. 

Always follow the manufacturer’s instructions when applying boiled linseed oil. This is the best way to get a perfect finish.

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