The wood joint is a popular term in woodworking. To combine wood pieces, we use different types of wood joints and tighten them with wood glue. After applying wood glue, clamping time is required for glue-ups.
Wood glue products have specified clamping times for stressed and un-stressed joints.
Most people wonder what’s the difference between stressed and unstressed joints. You would likely ask about the Stressed vs Unstressed joint.
Here’s what I learned:
A stressed joint carries a large dynamic load and an unstressed joint carries a small static load. After applying wood glue, stressed joints should clamp for about 24 hours and unstressed joint should clamp for about 30 minutes. Stressed joint needs to be stronger than an unstressed joint to carry the excess load.
But there’s more to know about stressed vs unstressed joint.
In this article, we’ll explore what’s stressed joint and unstressed joint with their applications and the differences between stressed and unstressed joint as well.
Let’s dive in deeper.
When I glue timber up I do it in small panels.. allow the wood to bend if it wants… I don’t put it under pressure to stay, I want it to be clamped up stress free.— Jamie Hubbard 🇬🇧 (@jam73e) October 24, 2018
Then thickness to get flat.
Then joint the faces of the next glue up (four faces of the 2 gaps ↔) pic.twitter.com/BCiAzf8Yee
What’s a Stressed Joint?
The stressed joint is a wood joint that carries a dynamic high amount of load. There’re so many reasons to become a wood joint stressed.
Chairs, tables, cabinetry, floors, and shelves have stressed joints that withstand high pressure from time to time.
To bear that amount of force, the wood joint must need to be strong.
When the stressed joint is properly glued and dried, it becomes stronger than wood fiber.
Stressed joint bond is seldom and able to withstand high forces focus on chairs, tables, cabinets, and doors during the day to day use.
Box joint (finger joint) and Mortise and tenon wood joints are extremely strong and apply for the areas that stress a lot. Therefore, those joints can be considered stressed joints.
When you’re working on wood joints if the position is stressed better to camp the stressed joint for at least 24 hours until the wood glue is completely cured and set.
Fun woodworking fact: when a joint is stressed, wood will break before wood glue breaks.— David Raffauf (@draffauf) September 30, 2019
Most stressed joints require mechanical fasteners with wood glue to reinforce the wood to meet the stress head-on.
The simplest fasteners are screws, nails, dowels, and biscuits. They support stressed joint to face the dynamic load without breaking the joint.
Above fasteners should apply to the stressed joint by cutting a hole and adding metal or wood to the intersection of the wood pieces.
After using both wood glue and fasteners you can see the stressed joint is satisfied and able to withstand high stresses.
Joints that are impacted by high dynamic stress need to be strong without ruining the appearance of the woodwork.
Examples for Stressed Joint
Here’re the wood joins that constantly withstand the dynamic stresses.
- Cabinet joints
- Floor wood joints
Let’s look at some 30 decade old joinery.— ☣surferjim is more stoked than you- regularly.🟩 (@surferjimw) June 19, 2020
Most joints were mortise and tenon with wood pegs. No nails or clue so they came right apart after 300 years. Amazing. Some old and new together. Notice the mortised floor joists into the header next to the stairs. Wild! 4/8 pic.twitter.com/Au7m8jwsBs
What’s an Unstressed Joint?
The unstressed joint is a wood joint that carries a small static load. Unstressed joints are not strong as the stressed joint.
Most of the time wood joint is well enough to carry a load when the joint is unstressed. No need for wood glue or fasteners.
But most woodworking experts recommend using wood glue even when the wood joint is unstressed as extra protection.
The clamping time for the unstressed wood joint is only about 30 minutes.
When you’re working on an unstressed joint like a window frame, window panels which are short clamps, clamping for 30 minutes is well enough and it takes about a maximum of 6 hours to get the wood glue fully cured.
Unstressed wood joints are mostly decorative joints that are not strong as stressed joints.
Butt joint and miter joints are examples of unstressed wood joints that use for areas with fewer stresses.
Titebond Polyurethane glue should clamp for about 45 minutes and the glue will be cured completely within 6 hours.
Even though we have mentioned 30 minutes clamping/ drying time for unstressed joint and a 24-hour clamping/ drying time for stressed joint, the drying time can differ because of the temperature changes, wood type, wood dryness, and humidity level.
- High temperature, lower humidity, and drier wood speed up the drying time.
- Lower temperature, higher humidity, and wet wood slow down the drying time.
Examples for Unstressed Joint
Here’re the unstressed wood joints that carry small static loads,
- Window panels
- Window frames
- Picture frames
Stressed vs Unstressed Joint Differences
So, let’s find out the differences between the stressed joint and the unstressed joint.
|Stressed Joint||Unstressed Joint|
|Withstand against heavy load||Withstand against small loads|
|Subject to dynamic load||Subject to static load|
|Strong wood joint||Wood joints are not so strong|
|Camping time is 24 hours||Clamping time is 30 minutes|
|Less durable||High durability|
|Need both wood glue and nails||Need only the wood glue|
|Difficult to work with||Easy to work with|
Types of Stress
Stresses are the forces that divide wood joints into stressed and unstressed joints. There’re main 4 types of stresses that impact wood joints. They are,
- Vertical shear
Among the above stresses racking is the most destructive stress. Those stress may tear the wood joint apart.
To withstand against above stresses wood joint, need to be strong and tightened with wood glue and fasteners.
The stressed wood joint can withstand against above stress, but if the applied stress is too much, stressed joints may also tend to break down.
- Compression stress – Forces are joint together
- Tension stress – Forces pull apart. Happen when an overloaded shelf is joined to a carcass with dado joints. The weight on the shelf pulls the shelf out of the dado.
- Vertical shear stress – Occurs when two halves of a wood joint slide against each other. This commonly happens with butt joints.
- Racking – Twisting and bending forces. This is the toughest stress for a wood joint. Even a stressed joint is hard to endure.
Top leg rail is a haunched tenon. Leg is attached to the apron via a dado housing joint with a wedge to prevent racking as the wood expands/contracts and helps make up for my inaccuracies (that brilliant design concept is by Paul Sellers). pic.twitter.com/stNBCKbAx2— Scott Piper (@0xdabbad00) June 12, 2020
As per recommendations for experts, never stress a new joint for at least 24 hours. Because the wood pieces are subjected to high stress at once, the wood fibers tend to break on their own.
Did I cover all you wanted to know about: Stressed vs Unstressed Joint with Differences
In this article, we have deeply discussed stressed vs unstressed joint, what is meant by stressed wood joint, what is meant by unstressed wood joint, the camping times of each wood joints, what are the major differences between stressed and unstressed wood joints as well.
The stressed joint is subjected to high dynamic stress which needs lots of attention. By applying wood glue and using fasteners you’ll be able to improve the strength of stressed joint and support wood fibers to withstand against high stress.
But with unstressed wood, you just have to apply wood glue for extra protection, and they live much longer than stressed joints.
Furthermore, I have discussed the uses of both stressed and unstressed joints and talked about the wood stress types and how their impact on the wood joints.
Hope you have gained pretty good knowledge about stressed joint vs unstressed joint with their differences.
So, let’s head into your next woodworking project and make sure to apply the correct wood joint for the correct position to avoid getting problems in the future.