It’s easy to get distracted by the rustic aesthetics of a charred wood surface, but did you know that its interior and exterior applications don’t provide the same durability? So, skipping the proper sealing process can lead to costly repairs in the long run.
In this article, I will discuss how to seal charred wood surfaces and select the right sealant for your project.
Charred Wood, Explained
The charring or Shou Sugi Ban process involves burning wood designs and patterns into a material by exposing it to an open fire. You may not know, but adding light burns into wooden boards allows the entire surface to withstand harsh weather conditions.
Preserving wood through this procedure also gives the charred surface an extra layer of protection against infestations. Given that most Shou Sugi Ban wood projects yield strikingly beautiful textures, it’s no surprise many woodworkers still practice this technique.
The History of Shou Sugi Ban and Its Process
Shou Sugi Ban projects have been around since the 18th century. It’s an ancient Japanese technique that also relates to the word “yakisugi,” which roughly means charring a Japanese cedar with an open fire.
To understand how this technique came to be, you must explore the term’s literal meaning. The word “Sugi” from Shou Sugi Ban refers to the cedar species in Japan, while “Shou” is the rough translation for durable, and “Ban” is the term for a wood plank.
While charred wood techniques gained popularity from their aesthetics, Japanese woodworkers burn the exterior siding of wooden planks for protection against weather and insect attacks.
Nowadays, DIYers use the Shou Sugi Ban siding technique as a modern decorative method for home improvement projects like doors and wood furniture pieces.
From there, the charred wood trend also expanded in the architecture industry. Some even resorted to using it to preserve untreated wood boards.
True to its name, making a charred wood workpiece only requires two things: the lumber board and the open fire. Use a propane torch if you don’t intend to burn the entire wood surface. It also provides more user control for a better-quality finish.
Getting the burnt-wood aesthetic you desire will only take 5 to 10 seconds of torching. Once the charred timber blackens, you must grab the wire brush to smoothen the soot in the wood surfaces. You can also use coarse sandpaper for this process.
The Shou Sugi Ban workpiece will leave a unique wood finish, so you don’t need to wonder why the patterns are different or why there are bumps on its surface.
Ideal Wood for Shou Sugi Ban (Interior & Exterior Applications)
Since its discovery, traditional woodworkers often execute the charred wood technique on Japanese red cedar materials. These tree species produce striking grain patterns after burning, so they’re perfect for wood furniture pieces.
Due to their notable porosity, these lumber boards possess a remarkable quality of retaining their durability and strength even after undergoing the Shou Sugi Ban process, where the wood is burned.
For woodworkers residing in the US, you can opt for western red cedar when working on a charring wood project. Like the Japanese specie, this hardwood creates stunning wood grain patterns even after torching its surface.
Moreover, this timber specie has excellent durability and strength, making them highly suitable for outdoor wood structures. If cedar materials aren’t available in your area, you can opt for hemlock, basswood, or pine.
Most of my recommendations are hardwood selections because they’re durable enough to withstand the charred wood process. Unfortunately, softwood species won’t work as burnt wood materials, mainly because the heat can make their weak structures crumble.
Since these projects range from floorings to exterior sidings, you must remember that not all lumber boards can serve as outdoor and indoor wood surfaces.
Why Seal Burnt Wood?
So you’ve decided to venture into the ancient art of wood charring or Shou Sugi Ban, and you’re probably wondering whether sealing that charred beauty is necessary. Let me clear the air: it absolutely is.
Traditional woodworkers don’t apply a coat of sealant after torching, but here are the perks you can expect by not skipping it:
Waterproof
I’ve heard people say that charring wood makes it waterproof. Not quite, my friend. All that charring does is create a carbon layer on the surface that can resist moisture to some extent.
Fortunately, a thin coat of sealant can protect the burnt surface from exposure to water and moisture. It’s something I always recommend not skipping.
Enhanced Wood’s Look
I’ve worked with charred wood for a variety of projects, and one thing I’ve noticed is how a simple sealant can drastically enhance its appearance. With just a thin layer of this product, the natural aesthetic of the charred timber will get highlighted.
Protects Burnt Wood Surface
Besides waterproofing, you can seal Shou Sugi Ban workpieces to help them withstand regular wear and tear. It can also shield the charred wood from the potential damage caused by changing weather conditions.
Increase Durability
When you seal charred wood pieces, it makes the surface more stable. With just a coat of sealant, the board can retain its natural beauty and structural condition for the longest time.
Great Base for Other finishes
Sealing burnt wood also improves surface adhesion. Because of this, the material can serve as an excellent base for other finishes you intend to apply in the future.
Protects Wood from Peeling, Chipping, and Cracking
If the charred wood materials you’re handling are coarse and exposed to high foot traffic, sealing the surface will ensure durability against potential peeling, cracking, or chipping. The thin coat can lessen the impact of wear and tear on the material.
Here’s the Best Way to Seal Burnt Wood
Materials You’ll Need
- Sealant for charred wood
- Staining product
- Brushes
- Air Compressor Tool
- Clean/Wet Cloth
- Vacuum Cleaner
Step #1: Brush it Down
Before you seal charred wood pieces, it’s crucial to eliminate dust particles and other residues on their surface. You must brush down the wood thoroughly to make it smooth and remove unsightly streaks, drips, and runs.
Running a brush through the wood prepares it for taking in the sealant. Besides that, this step also makes the surface more absorbent to any staining product.
You should know that charred wood often yields not-so-attractive patches, and smoothing them out with a clean brush is the easiest way to get a better finish.
Keep brushing until you see the charcoal layer take on a more brownish hue. I know it’s tempting to keep going until you get the exact shade you’re picturing, but let’s not get carried away. Over-brushing can ruin the wood, and nobody wants that.
Step #2: Clean the Wood Surface
Some residues may remain on its surface even after brushing the charred wood. I don’t advise leaving these particles in the material during sealing because it’ll dull the workpiece.
Here’s what you do: grab a lint-free cloth and gently wipe down the surface to get rid of any remaining debris. I like to follow up with a vacuum cleaner or an air compressor to eliminate any signs of dust particles.
Once the burnt wood is dust-free, wipe it down again with a wet cloth pre-soaked in soapy water. You can also pour this cleaning solution all over the surface to ensure cleanliness in every spot.
But a word of caution here: steer clear of harsh cleaning agents. You may not know, but these products contain strong chemicals that may damage burnt wood upon extensive exposure.
Before you proceed to the next step, ensure that the charred wood material is completely dry because it can hinder the sealing and staining process.
Step #3. Stain the Wood (If Needed)
Although this step is not typically part of the steps to seal charred wood materials, some woodworkers choose to stain to change the color tone of the board. Generally, these projects work best with brownish-black staining products.
But let me tell you: go easy on the stain. You don’t want to slather it on too thickly; that will just extend your drying time. Use the same brush you used for cleaning and work the stain into the wood, going with the grain.
While staining the charred wood, remember to add an even pressure in every brush stroke. If not, you’ll risk leaving the surface with noticeable streaks. You can apply two to three stain coats, but ensure each layer dries appropriately.
While the aesthetic advantage is a given, you may ask: does staining make charring wood waterproof? The short answer is yes. It enhances the material’s durability to stand against decay and rot. Because of this, I recommend it for outdoor projects.
Step #4: Seal the Wood
After drying and curing the stain, you can add the sealing product to the surface using a brand-new brush. Dip it into the solution and shake off the excess sealant. By doing this, you can spread it thinly and evenly.
Like staining, applying a sealant to burn wood requires brushing along the grain’s direction for enhanced durability and absorption.
One coat is enough to form a protective layer on the material. It would be best if you didn’t use too much sealant to prevent an extended drying time that may result in an unsightly finish.
Step #5: Dry and Cure the Wood
Whether sealing burnt wood or untreated boards, you must abide by the manufacturer’s label/instructions for proper drying and curing durations. If not, you’ll risk applying another coat of sealant too soon or too late, but it won’t yield your desired result.
Best Sealants For Charred Wood
Finding the right sealant for burnt wood projects isn’t the most straightforward task, mainly because of the bottomless choices in the market. Here are some you might encounter:
Spar Varnish
Although spar varnish isn’t a natural oil, it carries components that protect burnt workpieces from exterior elements like UV rays, moisture, heat, etc. On top of that, this product adds richness to the surface to enhance its natural color.
Listed below are some features you can expect from spar varnish when using them in Shou Sugi Ban projects:
- It offers excellent protection against UV exposure.
- The sealed wood has a higher chance of yellowing over time.
- Suitable sealant for interior and exterior wooden structures.
If you’re looking for reliable spar varnish, I’d suggest going for reputable brands like Rust-Oleum, Minwax, and Ola Masters.
Polyurethane
The reason why many woodworkers prefer polyurethane sealant over other natural oils is that it includes petroleum components. You may not know, but these materials allow the product to yield an even finish in different lumber types.
It offers excellent resistance to environmental elements like infestations, moisture, etc. Because of these attributes and its color enhancement features, the demand for a polyurethane sealant expanded to furniture making, cabinetry, and other woodworking projects.
Here are some features of polyurethane sealants that you must take note of:
- It has excellent workability and durability.
- You must apply it in thin coats for better results.
- Available in matte and glossy finishes.
Besides water-based polyurethane products from Rust-Oleum and Minwax, try to check out similar sealants from TotalBoat and Deft.
Polycrylic
This sealant should work well if you want to keep the natural aesthetic of the charred wood. It may have a clear finish, but it’s durable enough to handle the Shou Sugi Ban application indoors and outdoors.
If those attributes fit the bill for your sealing needs, here’s what you can expect when using polycrylic sealants for your burnt workpieces:
- It can stand against light scratches.
- Water-based variations aren’t prone to yellowing.
- It yields a clear finish.
While you have many options for buying polyacrylic sealants, the commercial brands that carry the best selections for this product are Minwax and General Finishes.
Danish Oil
Besides rich and glossy finishes, Danish oil can provide solid protection to prevent wood surfaces from peeling and cracking. Upon drying, it forms a solid film that waterproofs the material to block rot and decay.
If you choose to apply Danish oil on burnt wood, these are the features you’ll encounter:
- It’s safe for food contact because it’s non-toxic.
- It needs priming before staining or sealing.
- It’s easy to use because it hardens immediately.
Typical sealant manufacturers don’t carry Danish oil on their shelves. So if you need one, try the products from Watco, Tried & True, or Rustins.
See Also: Pros and Cons of Danish Oil
Resin
Epoxy resins will work great if your charred wood experiences mechanical impact regularly. This sealant’s high tolerance level is perfect for countertops and tables since it can withstand scratches, cracks, and peels.
Check out other features this sealant can provide:
- Natural wood aesthetic enhancement.
- It covers the material with solid UV protection.
- Its oil-based attributes may cause it to turn yellow over time.
Among the epoxy resins for wood projects, Superclear Premium is the better option for durable sealing tasks. But is epoxy resin food safe? Let’s find out next!
Linseed Oil
Linseed is one of the most famous traditional wood oils used in sealing wood materials. It’s an eco-friendly alternative for burnt wooden materials, especially if you want them to be food-safe.
It’s also called tung oil and shares non-toxic features with a shellac sealant. Have a look at its attributes:
- It covers dents and scratches very well.
- Non-toxic and eco-friendly alternatives.
- Flexible and easy to use.
My personal favorite for linseed wood sealants is the one from Furniture Clinic. Besides the affordable price range, it has a quick-drying attribute that requires a well-ventilated area.
Furniture Wax
If you’re not a fan of artificial aesthetics [1], furniture wax is the best sealing agent for charred wood. It enhances the material’s natural appearance without the risk of toxic exposure. Since this product doesn’t penetrate deep, it’s more geared for the sheen.
Here are some results you can expect once the furniture wax dries on the wood’s surface:
1. It’ll yield a smooth and soft surface finish.
2. It can highlight the material’s natural beauty.
3. Unfortunately, it offers no UV protection.
You can buy the best furniture wax for your Shou Sugi Ban project from brands like Minwax, Renaissance, and Beeswax.
My Top Sealants for Burnt Wood
1. Varathane 200061H Water-Based Ultimate Polyurethane
As a sealant that dispels stains and scratches, Varathane 200061H is the perfect choice for charred wood used in indoor projects like cabinets and windows.
2. Rust-Oleum 207008 Marine Spar Varnish
You can count on Rust-Oleum 207008 to yield a crystal-clear finish and durable coating suitable for outdoor Shou Sugi Ban workpieces.
3. Sunnyside Corporation 87332 Pure Raw Linseed Oil
Unlike other sealants, Sunnyside Corporation 87332 penetrates deep into the wood. Because of this, it’ll work well with charred furniture pieces and antiques.
Tips and Tricks in Sealing Charred Wood
Test First
You can avoid buying the wrong sealant by checking if the wood reacts well with the product. The testing involves applying the sealing agent in a small section and waiting 24 hours to see the results.
Use A Light Hand
You should seal and clean the burnt material as gently as possible. Like it or not, charred wood is a delicate material with a high chance of getting damaged when incorrectly handled.
Well-Ventilated Space
Staining and sealant products often dry quickly, so executing these procedures in a well-ventilated area is crucial. It also prevents you from breathing in toxic fumes and debris.
Application Patterns
If you don’t create a consistent pattern during the sealant application, you’ll likely have an uneven and unsightly finish. Go slowly and start in the middle for better results.
Do You Need To Seal Wood After Burning?
Sealing burnt wood is a step you can skip. However, I would still recommend doing it for charred projects placed outdoors. As mentioned, torching the material isn’t enough to protect the surface from elements like water, moisture, or heat.
Does Charred Wood Requires Maintenance?
Yes, charred materials need maintenance. However, it requires less than typical wood pieces. If you seal its surface, the workpiece can last up to 10 years without resealing. Unless, of course, the material has high exposure to harsh conditions.
Conclusion
While learning how to seal charred wood isn’t the most common woodworking knowledge, trust me when I say it’ll be a valuable skill set in the long run.
Besides creating unique workpieces, understanding this task will prevent you from wasting time and money on the wrong sealing and staining products.
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
- Makita XCU03PT1 Review (2023) — A Cordless Chainsaw Powerhouse - November 29, 2023
- Greenworks 24V 13-Inch Brushless Push Lawn Mower Review (2023) - November 29, 2023
- Ryobi P1108BTL One+ Review (2023) - November 27, 2023
