How to Keep Wood from Splitting and Cracking

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Dealing with splitting and cracking in wood can be frustrating, as it compromises the durability and aesthetic appeal of your wood carving and working projects.

Thus, our expert woodworkers will share how to keep wood from splitting by addressing key factors such as wood selection, cutting techniques, and protective treatments. Learn how to prevent these common issues and enhance the longevity of your wooden creations.

Reasons Why Wood Splits

Typically, wood cracking occurs when the wood fibers within the wood grain expand or contract beyond a certain threshold, leading to separation or breakage. This expansion or contraction is often a result of:

Changes in Moisture Content

Wood absorbs moisture and is prone to breakage if stretched beyond its limit.

Humidity changes cause splitting, with low humidity leading to moisture loss and pore wood shrinkage while excessive moisture causes pore expansion, leading to breakage, especially in porous wood types.

Avoiding wood splits

Direct Impact

Improper nailing, screwing, or dropping wood can break wood fibers. Oversized fasteners with dense wood cause cracks. The nail or screw acts as a wedge, increasing internal stress and causing wood fibers to separate, leading to cracking or splitting.

10 Effective Methods to Stop Wood From Splitting and Cracking

Method #1: Salt Solution

A salt paste can reduce wood moisture and prevent warping. To do this, mix table salt and water in a bucket, adjusting salt to water ratio. Ensure a well-mixed, unsaturated solution without salt at the bottom. Wait four hours before continuing.

Step #1: Add Cornstarch

After four hours, add cornstarch to thicken the salt paste. Thickness affects drying and moisture absorption. The thicker salt paste dries slower and can absorb more moisture. Adjust as needed.

Step #2: Add Egg

Next, add a few eggs to the mixture and blend thoroughly for even incorporation. Eggs contribute to the hardening of the solution while maintaining a softer consistency for ease of application to surfaces.

Step #3: Apply Salt Paste To Wood And Dry

Use a paintbrush to apply the salt paste evenly on the wood, including corners and edges. Dry for 24 hours in a warm space. Thicker layers take longer to dry. Salt paste prevents wood from splitting by removing excess moisture.

applying salt paste on wood

Method #2: Varnish

Varnish prevents wood from splitting, seals, and enhances its appearance. Hard coatings like lacquer, shellac, or polyurethane provide durability. Most often used on wooden boat decks, it also enriches wood color and natural grain for an appealing look.

Materials

Step #1: Sand With Fine-Grit Sandpaper

Sanding is vital for varnish application. Dry the wood before sanding to achieve a smooth wood surface for better varnish absorption. Finer grit sandpaper, like 220 grit, opens up the wood grain, improving absorption.

Step #2: Clean the Wood’s Surface

Clean wood before varnish application, especially after sanding. Remove sawdust [1] and dirt to avoid interference with varnish. A quick cleaning with a damp cloth or rag will suffice.

Step #3: Prepare Varnish

Follow varnish instructions and ratios closely. Wear protective gear like gloves, goggles, and a mask, especially in poorly ventilated areas. You can use protective equipment for varnish preparation, similar to that used for house painting.

varnishing wood

Step #4: Apply Varnish And Dry

Apply varnish evenly with a paintbrush. Work quickly to apply a thin layer, as the varnish dries fast. Allow each layer to dry before applying more. Follow drying times if using polyurethane. Apply varnish to dry wood to avoid uneven appearance.

Step #5: Repeat As Needed

Apply varnish in multiple layers. After 2-3 layers, let the wood dry completely. The number of layers required depends on the wood type and desired protection. At least three layers are recommended for a thick, protective barrier to prevent wood splitting.

Method #3: Sealant Or Stabilizer

Sealants and stabilizers, similar to varnishes, offer benefits beyond preventing the wood from splitting.

A high-quality sealer not only inhibits splitting but also protects wood against warping or expansion caused by external and environmental factors. You can also make your own by mixing wood glue to prevent wood split.

Step #1: Sand the Wood Using Fine-Grit Sandpaper

Sand wood before sealing to create a smooth wood surface for better adhesion. Use 220-grit sandpaper for optimal absorption. Finer grit may alter the grain, while coarser grit can cause an uneven drying appearance.

sanding wood

Step #2: Clean The Wood

After the sanding process, it is essential to thoroughly clean the wood surface to eliminate any accumulated dust, debris, and sawdust. Failing to remove these particles can negatively impact the final appearance and result in an uneven coating. 

Once the cleaning is done, it is recommended to allow the wood to dry for a full 24 hours to ensure complete drying, which is crucial for achieving optimal adhesion of subsequent layers or finishes.

Step #3: Apply the Sealant/Stabilizer And Let it Dry

Sealants and stabilizers have varying compositions and application methods, like spray-on or liquid. A spray-on sealant may need multiple layers, while a thicker liquid sealant needs fewer. Wait 48 hours before applying a second coat for optimal results.

Method #4: Boiled Linseed Oil

Boiled linseed oil is popular among woodworkers for its rich color, texture, and protection. Safe for beginners, it adds attractive color to wooden projects.

Materials needed

Step #1: Sand the Wood

The crucial initial step is to sand the wood, ensuring optimal bonding with the linseed oil. Failing to sand the wood surface may prevent proper absorption of the oil and result in an uneven coat.

using linseed oil on pine wood

Step #2: Clean The Wood Surface

Post-sanding, it’s essential to remove any residual debris. With this oil, dust, and debris can obstruct the oil from evenly reaching the wood, causing uneven drying or coating.

Step #3: Apply Boiled Linseed Oil And Dry

Apply boiled linseed oil to the wood’s entire surface, using thin layers for quick drying and additional laters.

Typically, two to three layers offer protection, but ensure the wood dries completely and not partially dried wood to avoid a splotchy finish when you apply linseed oil.

Method #5: Seal With Paintable Wax

Paintable wax serves as an affordable solution to prevent the wood from splitting and cracking, particularly for greenwood, offering protection while maintaining cost-effectiveness. Before applying paintable wax, ensure you have the following equipment on hand:

Step #1: Prepare the Wax

maple wood candle holder

Make wax without buying it: Break wax candles into small pieces and weigh them. Melt wax in a container and pour 1/4 of the wax’s weight of paint thinner into a jar. Add melted wax and shake well. Prepare it for wood application.

Step #2: Apply the Wax

Use a paintbrush to apply wax in thin, even coats, covering the wood entirely. Apply light coats for quick drying and minimal errors. Use uniform pressure.

Method #6: Fill Wood With Epoxy

Epoxy fills wood cracks and creates a strong bond. Available in various colors, it blends with wood to become almost invisible. Clean and dry the wood before applying, and follow instructions for optimal results.

Before filling wood splits and cracks with epoxy, gather the following equipment:

Step #1: Wood Preparation

To guarantee proper epoxy adhesion, begin with a clean, dry surface. Smooth any rough edges or bumps that could hinder the epoxy from filling the split or wood crack using sandpaper. This step is essential for a successful repair.

Step #2: Mix Epoxy

putting epoxy on wood

For a strong bond, thoroughly mix the epoxy resin and hardener, adhering to the instructions on the packaging. The epoxy begins to set once combined, so swift work is crucial.

Step #3: Apply the Epoxy

Utilize a putty knife to apply epoxy into the wood’s split or crack, ensuring it’s filled. For larger surface areas, you can use a paintbrush. Adequately fill the split or crack with epoxy.

Step #4: Secure the Wood

For larger splits or cracks, secure the wood with tape or clamps during the epoxy drying process, ensuring proper setting and a robust bond. Confirm the wood is stable and level before allowing it to dry.

Step #5: Dry It

Patience is crucial, as epoxy requires time to dry and set effectively. The drying time depends on the size and depth of the split or crack. After the epoxy dries, sand down excess material for a smooth surface, taking care not to remove epoxy filling the split or crack.

drying epoxy on wood

Method #7: Use Screws, Not Nails

Screws help to keep wood from splitting and cracking better than nails. Nails lack holding power and cause wood to shift, leading to splits and cracks. Screws provide a strong grip, keeping the wood firmly in place.

Using screws ensures a secure and long-lasting structure, unlike nails which can make a wooden bench wobbly and unsafe over time.

Step #1: Pick the Right Screws

Ensure the screws used are long enough to penetrate both wood pieces being joined. Opt for screws with a wider diameter than nails for improved grip and stability.

Step #2: Pre-Drill Holes

To prevent the wood from splitting, use a drill bit marginally smaller than your screw and drill a hole through only the top piece of wood.

Step #3: Counter-Sink the Holes

Countersinking involves drilling a larger hole atop the pre-drilled hole, enabling the screw head to sit flush with the wood’s surface, providing a polished and professional appearance.

drilling holes on wood

Step #4: Insert Your Screws In

Utilize a screwdriver or drill to insert the screws, ensuring you don’t overtighten, as this could lead to wood splitting.

Method #8: Store Your Wood Properly

Proper storage of wood is crucial in preventing splitting and cracking, even in extreme circumstances. Follow these tips to store your wood effectively:

Method #9: Dry Your Wood Naturally

Air-drying is a chemical-free way to keep wood from splitting but it may warp without proper precautions. Stack wood on cinderblocks in a dry, warm area shielded from weather elements. This setup prevents warping and enables higher stacking, conserving space.

Method #10: Choose the Right Wood Type

To minimize the risk of splitting, consider selecting the appropriate wood type. Older woods, those with thicker cell walls, and knotty or burl woods with uneven or twisted grains exhibit greater resistance to cracking. Conversely, straight-grained woods are more prone to splitting.

Maintaining a list of naturally split-resistant woods can be helpful. Some top choices include:

choosing best wood

Other popular, less-split-prone woods are walnut, yellow poplar, cherry, and oak. Additionally, consider moisture-treated boards.

Timber yards often use linseed or tung oil, a sealant (such as polyurethane, varnish, or lacquer), or a stain-sealant combination to treat wood for moisture resistance.

Ways to Repair And Fix Split or Cracked Wood

Repairing wood splits typically involves filling with wood filler, epoxy, or glue, followed by clamping, sanding, and staining. For larger splits, use filler or replace damaged wood. Wood glue, with proper clamping, can effectively fix most splits.

Some recommended products to repair cracked wood include:

How To Prevent Wood From Cracking?

Fill With Wood Sealer or Epoxy

To repair cracked or split wood, wear protective gear, and mix epoxy resin and hardener, optionally add wood-colored dye. Then, fill the crack, let it dry overnight, and then remove excess epoxy and sand the area.

staining with Olympic Maximum Wood Sealer For Decks

Use Wood Glue & Sawdust

For a quick fix, apply wood glue to cracks or splitting wood, cover with matching sawdust, let dry overnight, and sand for a smooth finish.

Utilize Wood Putty or Filler Sticks

Purchase wood putty or filler sticks, and apply them to cracks in the wood, overfilling slightly. Smooth and remove excess material, let dry for eight hours, then sand with 120-grit followed by 220-grit sandpaper for a smooth finish.

How To Keep Wood from Cracking and Splitting Under Different Tasks

When Sawing

To avoid wood from splitting during sawing, use a sharp, high-tooth-count saw and masking tape on the cut line. Cut gently, align with the cut direction, and stabilize the wood with a clamp or vise. Proceed slowly with minimal pressure for a clean, split-free cut.

While Screwing

To avoid wood splitting when screwing, drill a suitable pilot hole and lubricate the screw with paraffin wax. For thin wood pieces, use bolts and nuts instead of hinges for a strong, split-free connection.

When Drying

Prevent splitting when drying wood by applying sealants or stabilizers, such as salt paste, varnish, paintable wax, or boiled linseed oil to stop wood cracking.

These products act as moisture barriers, preventing evaporation and penetration of too much moisture, and reducing splitting, cracking, and water damage.

drilling wood

While Drilling

To prevent cracking when drilling wood, create a pilot hole for smooth thread cutting and straight drilling. Additionally, select appropriate wood boards and drilling points for your project.

Tips to Avoid Splits/Cracks on Wood

Can You Use Linseed Oil or Polyurethane to Stop Wood From Cracking?

Polyurethane effectively prevents wood splitting when applied correctly, serving as a moisture barrier and protecting against wear and tear.

Linseed oil, particularly boiled linseed oil, also prevents wood cracking by shielding the surface from moisture-induced expansion or contraction.

applying oil

FAQ

What's the proper way to dry cedar wood without cracking?

To dry cedar wood without cracking, apply a varnish or polyurethane coating to prevent water absorption and moisture evaporation, which causes cracking. Also, avoid exposing the wood to dry air, a significant factor in cedar cracking.

How can you dry wood faster without cracking?

To quickly dry the wood without cracking, place it against a wall or in a warm, well-ventilated area, allowing it to dry slowly and evenly for a week. Avoid direct sunlight, as it can cause sudden, uneven moisture loss, leading to splitting and cracking.

More article guides for you

Conclusion

Knowing how to keep wood from splitting is crucial for maintaining the integrity and longevity of your wood furniture and other woodworking projects.

By selecting the right wood type, using proper cutting and drilling techniques, and applying suitable sealants and treatments, you can effectively prevent splits and cracks, ensuring your creations stand the test of time.

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson
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