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[Dmitry_CAD]

Hello everyone,
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Introduction
In this topic, I would like to introduce myself — my name is Dmitry, and I am a soft furniture designer and developer, working directly in furniture construction and production.
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What I will share here
Here I will be sharing practical insights, production secrets, and important technical details that are usually learned only through hands-on workshop experience. The goal is to discuss real manufacturing nuances, improve quality, and exchange useful knowledge about upholstery and soft furniture construction.
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Weekly content
In addition, I will be posting a new recommendation or practical production tip once a week in each new message, focusing on different aspects of soft furniture manufacturing technology.
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Community
I hope this will be useful for both beginners and experienced professionals, and I also look forward to your own tips, discussions, and experience.
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Contact
If you have any questions regarding the design and development of soft furniture, as well as furniture for yachts, aircraft, automobiles, or motorhomes, feel free to contact me at:
dmitry.softfurniture@gmail.com

[Dmitry_CAD]

How to Properly Install a Bed Mechanism Gas Spring

Install the gas spring with the thick cylinder facing upward and the thin extending rod facing downward.

Why is this important? Because inside the cylinder there is oil that lubricates the internal seals and gland seals, and also provides soft cushioning at the end of the stroke. When the bed is closed and lowered, the oil flows down toward the rod seal. This prevents the rubber from drying out, eliminates gas leakage, and extends the service life of the gas spring several times over.

The gas inside the spring is under extremely high pressure. To prevent it from escaping through the gap between the moving rod and the cylinder wall, special rubber seals are used. The oil continuously lubricates these seals, preventing them from drying out, cracking, and allowing the gas to escape.

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[Dmitry_CAD]

What Happens If You Choose the Wrong Gas Strut Force for a Lift-Up Bed?

Choosing the wrong gas strut force (measured in Newtons) can lead to serious problems and even create safety risks.
If the gas struts are too strong, the metal bed frame and mattress may shoot upward as soon as you start opening the bed. This can be dangerous and may cause injuries.
Closing the bed will also become difficult. You'll have to apply a lot of force—sometimes almost hanging your entire body weight on the bed—to lower it.
Over time, this becomes an exhausting daily workout.

Since gas struts are constantly under pressure, excessive lifting force puts continuous stress on the bed hardware. This can gradually:

• Loosen or damage the mounting bolts.
• Deform the side panels of the bed where the lifting mechanism is attached.
• Even bend the metal bed frame over time.

If the gas struts are too weak, you'll face the opposite problem.
The struts won't be able to support the weight of the bed, meaning you'll have to lift most of the load yourself.
A weak gas strut also won't hold the bed securely in the open or partially open position. The frame and mattress may suddenly fall while opening or closing the bed, creating a serious safety hazard.
Because undersized gas struts are constantly working at their limit, the internal piston seals wear out much faster. Gas begins to leak, and the struts may fail completely after only a few months.

How to Choose the Correct Gas Strut Force
Always calculate the total weight that the gas struts will actually lift:

• Metal bed frame with slats
• Mattress
• Blanket or comforter
• Pillows
• Any other bedding that stays on the bed while lifting

Choosing the correct force will ensure:

• Smooth and effortless operation
• Safe opening and closing
• Longer service life for both the gas struts and the lifting mechanism

In short, simply add up the total weight that the gas struts will actually be lifting. Choosing the correct force will ensure smooth operation, safe use, and a longer service life for both the gas struts and the lifting mechanism.

The next step is determining the correct gas strut force in Newtons (N) based on the total weight of the bed assembly. In the following post, I'll explain how to calculate the required force and choose the correct gas struts in Newtons.

[Dmitry_CAD]

Also, check out my guide on pantograph sofa bed transformation mechanisms here: https://www.theupholsteryforum.com/view ... f=6&t=9261

[Dmitry_CAD]

How to Choose the Right Gas Struts for a Bed Lift Mechanism

So, how do you correctly calculate the Newton (N) rating for gas struts?

Let’s take an example: we have a metal frame with a lift mechanism measuring 2000 x 1600 mm, weighing 25 kg. The mattress is also 2000 x 1600 mm, with a thickness of 200 mm and a weight of 25 kg. This gives us a combined total weight of 50 kg.


The Golden Rule:

The quick rule of thumb here is to simply add a zero to the total weight in kilograms. In our case, 50 kg becomes 500 Newtons.

This means that for a total frame and mattress weight of 50 kg, you will need two 500N gas struts. As a pair, they provide 1000 Newtons of lifting force.

Given the acute angle of a standard bed lift mechanism, this force is just right to hold up 50 kg. This is the standard calculation method. However, in practice, you also need to factor in the specific design of the lift hardware itself.


Testing the Setup:

To get the perfect fit, start by installing two 500N struts and test the movement:

• The frame and mattress should lift easily with one hand.
• It must lock securely at the highest point.
• It should close smoothly without requiring excessive force.

Adjusting the Force:

• If it doesn't stay up: Step up the power by adding another 100N — meaning you should swap them for 600N struts. Opting for 600N struts is also a smart move if that initial 50 kg didn't account for heavy blankets, quilts, or large decorative pillows.
• Up to 700N: In some cases, depending on the specific lift mechanism, you might even need 700N struts. But don't go any higher than that!
• Too strong (700N+): The bed will be incredibly hard to close, or you might not be able to close it at all.
• Too weak (400N): Don't drop down to 400N either. The frame and mattress won't stay open, and the bed will keep shutting on its own when you try to open it.

[Dmitry_CAD]

Sofa frame

If you want to prevent the sofa from squeaking during use, make sure to apply PVA glue to all joints when assembling the frame!

[Dmitry_CAD]

Foam Joint

Why shouldn't you form a rounded seat edge like shown in the photo?

Foam has high elasticity and always tries to return to its original shape. When you glue it butt-to-butt on a curve, it creates constant tensile stress. As a result, the glue will quickly fail, and the joint will pull apart.

This is especially true for the front edge of a seat, which constantly experiences heavy loads whenever someone sits down or stands up. You should avoid doing this.

But if you are in a tight spot, have absolutely no other options, and must join it this way, make sure to glue a layer of non-woven fabric (interlining) right over the joint.

It will take the load and prevent the foam from splitting apart!

[Dmitry_CAD]

What do the stripes on furniture elastic webbing mean?

What do the stripes on furniture elastic webbing mean? While Chinese manufacturers use one stripe to indicate the stiffest webbing and four stripes for the softest, Turkish manufacturers do the exact opposite: one stripe means the softest, and four stripes mean the stiffest. Keep this difference in mind when purchasing, and always check the elasticity percentage just to be safe!

Below, I will be breakdown the characteristics of Chinese furniture elastic webbing :

One stripe indicates elastic webbing with 20% to 30% stretch. It offers the highest stiffness and tensile strength.

Where is it used?
* Sofa and armchair seat bases: Used exclusively in areas subjected to maximum and constant weight loads. This is the main load-bearing element that replaces or complements the spring unit. The webbing supports the weight of people sitting and prevents the seat from sagging over time.
* Office and kitchen chairs: Due to the thin layer of foam in chairs, the base must be as stable as possible so that you don't feel the wooden frame.
* Pull-out sleeper mechanisms: Applied directly in the bases of convertible beds.

Two stripes indicate elastic webbing with 40% to 50% stretch. It belongs to the medium stiffness category.

Where is it used?
* High-comfort sofa and armchair backrests: For example, in loungers. It reliably supports the weight of a leaning person.
* Chairs and small armchairs: Used in seating areas where the seat depth is relatively shallow.
* Soft, voluminous headboards and beds: Perfect for tufted (Chesterfield) headboards, where an elastic base is required to fix thick foam.
* Combined layout: Often used in combination with one-stripe webbing. The two-stripe webbing is placed at the edges of the seat, while the stiffer one-stripe webbing is placed closer to the center.

Three stripes indicate furniture elastic webbing with 60% to 70% stretch. It falls into the category of soft, highly elastic webbings.

Where is it used?
* Sofa and armchair backrests: This is its primary application. It is used in areas where holding critical weight is not required, but maximum softness is key. It flexes gently under the back, creating a feeling of comfort and relaxation.
* Armrests and headrests: Used to create voluminous, soft, and rounded armrests. This is especially true for classic sofas, where the webbing acts as a pliable frame beneath the foam layer.

Four stripes indicate super-elastic webbing with 80% to 100% stretch. It is used in furniture manufacturing where you need to achieve a maximum "sink-in" and enveloping effect.

Where is it used?
* Bed headboards: Ideal for deep tufting with thick foam layers, where the base needs to deflect deeply inward while forming folds.
* Top comfort layer of multi-layered seats: It is stretched over rigid one-stripe webbing (with an insulating layer between them) to soften the top seating area of premium sofas.
* Complex curved frames: Used where the webbing must perfectly conform to non-standard shapes without causing fabric wrinkles.