Why Wet Wood Sucks

Ever wondered why some furniture lasts forever while others warp and crack in months? The secret sauce happens way before any chisel gets involved: kiln drying. 🪵🔥

For true craftsmen, kiln-dried wood isn't just a preference—it's a must. This process transforms raw lumber into a stable, reliable material that is the backbone of quality furniture. But why is it so important? And how does it impact the furniture in your home?

Let's walk through the (rather complex) world of kiln drying. We're gonna get real nerdy here, so skip to the bottom if you just want the short and sweet of it. 😉

Take a sneak peak at our kiln operation in Weldona, CO.

Understanding Kiln Drying

Definition

Kiln drying is a controlled method of removing moisture from wood using heat, humidity and air circulation. This process involves placing lumber in a large, insulated chamber, called a kiln, where temperature and humidity are carefully regulated. The wood is subjected to specific drying schedules, which vary depending on the species, thickness and desired moisture content.

Stage	Temperature	Relative Humidity	Duration
Initial	100-120°F	80-90%	2 weeks
Drying	140-180°F	30-60%	2-4 months
Conditioning	160-180°F	70-80%	2-4 weeks

Comparison with Air Drying

While air drying is a natural process, kiln drying offers several advantages:

• Speed: Kiln drying can be completed in days (vacuum kiln) or months (dehumidifier kiln), whereas air drying can take years.

• Consistency: Kiln drying provides more uniform moisture content throughout the wood.

• Control: It allows for precise moisture content targeting, crucial for furniture making.

• Pest Elimination: The high temperatures kill insects and fungi.

Types of Kilns

Furniture makers use many types of kilns, each with very different features:

1. Conventional Kilns

   • Most common

   • Use steam heat and vents for humidity control

   • Suitable for large-scale operations

2. Dehumidification Kilns

   • Energy-efficient

   • Recirculate air and remove moisture

   • Ideal for smaller batches

3. Vacuum Kilns

   • Fastest drying method

   • Operate at lower temperatures

   • Excellent for valuable or sensitive woods

4. Solar Kilns

   • Eco-friendly option

   • Use solar energy for heat

   • Cost-effective for small-scale operations

Now that we've explored the basics of kiln drying, let's examine the specific benefits this process offers to furniture makers.

All of our slabs at Just Rustic have been meticulously dried in our Nyle dehumidifier kiln.

Benefits of Kiln-Dried Wood

Improved Stability

Kiln-dried wood offers superior stability for furniture making. The controlled drying process significantly reduces the wood's moisture content, resulting in a more stable material. This stability is crucial for creating long-lasting, high-quality furniture pieces.

Aspect	Green Wood	Kiln-Dried Wood
Moisture Content	30-200%	6-8%
Dimensional Stability	Low	High
Risk of Warping	High	Low

Reduced Warping and Cracking

One of the most significant advantages of kiln-dried wood is its resistance to warping and cracking. The controlled drying process minimizes internal stresses, reducing the likelihood of these common issues:

• Twisting

• Bowing

• Cupping

• Checking

  
  

This resistance to deformation ensures that furniture maintains its intended shape and structure over time, even in varying environmental conditions.

Enhanced Durability

Kiln-dried wood boasts enhanced durability, making it ideal for furniture that needs to withstand daily use and environmental changes. The drying process:

1. Eliminates most insects and fungi.

2. Hardens the wood fibers.

3. Increases overall strength.

   
   

These factors contribute to furniture that lasts longer and maintains its integrity, even in challenging conditions.

Color Consistency

Another important aspect of quality assurance in kiln-dried wood is color consistency. The controlled environment of a kiln allows for:

• Even color development throughout the wood.

• Reduction of discoloration caused by fungi or minerals.

• Improved aesthetics in the final product.

Better Finish Quality

Furniture makers appreciate kiln-dried wood for its superior finish quality. The controlled moisture content allows for:

• More consistent staining and painting.

• Improved adhesion of finishes.

• Reduced risk of finish failure due to moisture-related issues.

Ever seen a table top with finish that's flaking off? More often than not, this is caused by moisture in the wood trying to seep out through the surface. We have customers come to us all the time with refinishing projects for this very reason. Their wood wasn't dry when the table was built. Dry wood allows for a smoother, professional appearance that maintains its beauty for years to come.

Example of a table base with severe cracking / warping -- constructed from wet wood.

Moisture Content Control

Ideal Moisture Levels

For furniture makers (especially in our harsh Colorado climate), achieving the right moisture content is crucial. The ideal moisture level for indoor furniture typically ranges from 6% to 8%. This range ensures stability and minimizes the risk of warping, cracking or other defects.

Wood Type	Ideal Moisture Content
Hardwoods	6-8%
Softwoods	7-9%
Exotic	6-8%

Preventing Movement

Kiln drying helps prevent future wood movement by:

• Equalizing moisture content throughout the wood.

• Relieving internal stresses in the wood fibers.

• Hardening the wood's cell structure.

  
  

These factors contribute to dimensional stability, reducing the likelihood of warping, twisting or cracking as the furniture ages.

Consistency

One of the key advantages of kiln-dried wood is the consistency it offers across multiple pieces. This uniformity is essential for furniture makers because:

1. It allows for precise joinery and fitting.

2. Ensures even staining and finishing.

3. Reduces the risk of mismatched components in a single piece of furniture.

   
   

By using kiln-dried wood with consistent moisture content, craftsmen can create high-quality, long-lasting pieces that maintain their integrity over time. This level of control and predictability is invaluable in crafting furniture that meets both aesthetic and functional requirements.

When You're Shopping -- Buyer Beware

Identifying Properly Dried Wood

When selecting wood for your next project, it's crucial to know how to identify properly dried lumber. Here are the big things to look for:

• Moisture Content: Use a moisture meter to ensure the wood is at the appropriate level. We use Wagner Meters.

• Appearance: Look for uniform color and minimal warping or twisting.

• Weight: Properly dried wood feels lighter than its green counterpart.

• Sound: Dry wood produces a higher-pitched sound when tapped.

• Price: If the deal seems too good to be true, it probably is.

Indicator	Properly Dried Wood	Improperly Dried Wood
Moisture Content	6-8%	>12%
Appearance	Uniform color, minimal warping	Discoloration, visible twisting
Weight	Lighter	Heavier
Sound	High-pitched	Dull thud
Price	Hardwoods: $15+ per bd ft Softwoods: $8+ per bd ft	Hardwoods: <$10 per bd ft Softwoods: <$5 per bd ft

Working with Suppliers

Establishing a good relationship with reliable suppliers is key. Consider the following to keep yourself from ending up with wet wood:

1. Research reputable suppliers in your area. Be skeptical of the random Facebook marketplace sellers who are ready to give you a "killer deal."

2. Trust but verify. BYO moisture meter and test some samples before making large purchases.

3. Inquire about their drying process and quality control measures. If they can't intelligently answer your questions, there's a good chance the wood they're selling hasn't been properly dried.

   
   

Understanding Grading Systems

Familiarizing yourself with wood grading systems helps in selecting the right quality for your projects. Different countries and organizations use varying systems, but common grades include:

• FAS (First and Seconds): Highest quality, minimal defects

• Select: High-quality with slightly more defects than FAS

• No. 1 Common: Good quality with more knots and defects

• No. 2 Common: Lower quality, suitable for rustic projects

  
  

When choosing kiln-dried wood, consider the project requirements and balance quality with cost-effectiveness. With proper identification, supplier relationships, and grading knowledge, you can make sure you're working with the best materials.

The Cliff Notes

Let's recap real quick for the cheaters in class who skipped down to the conclusion.

1. Indoor furniture should be built with wood properly kiln dried to a moisture content of 6-8%. Especially in a climate as harsh / dry as Colorado.

2. Air-dried wood works too, but it usually takes years to get it dry enough. And even then it won't be as consistent as kiln-dried wood.

3. Building with wet wood leads to big problems down the road, including warping, cracking, cupping and flaking finishes.

4. Buyer beware! Not all suppliers are created equal. If the price / deal seems too good to be true, it usually is. And you just hauled a bunch of wet wood home.

   
   

Whether you're an experienced craftsman or just breaking into the woodworking scene, save yourself the trouble and start with the right ingredients. Just like the foundation under your house, the moisture content in your wood single-handedly determines how long your project will stay standing.

Trust me. I've tried it the hard way. That's why our kiln drying process at Just Rustic is borderline OCD. This stuff matters.

Questions?

Or just want to wood-nerd out some more? Drop me a note at jason@justrusticco.com.

Stay dry, my friends!

~ Jason