Less Smoke from the Fire: How Our Stainless Steel Double-Wall Insert Works

A nice fire doesn’t really require much: good wood, a high-quality fire pit, and a little time. However, what can quickly make an evening on the patio in densely populated residential areas less pleasant is smoke—especially when it might bother the neighbors. Normally, smoke can be minimized significantly by using completely dry, high-quality firewood. But if you want even less smoke, this article is just what you need.

Smoke-free or significantly smoke-reduced fire bowls solve the smoke problem with a special airflow system and what’s known as secondary combustion. Until now, however, this usually meant that anyone who wanted to use this technology had to buy a completely new fire bowl. A new fire bowl that, on top of that, isn’t of good quality—because to this day there is no German manufacturer, and the material thickness in this industry remains a meager 0.8 mm—cannot provide long-lasting use or a durable appearance. Virtually all smoke-free fire bowls on the market are imported from the Far East, flooding the German market with products made of flimsy materials.

That is exactly where we at Stahlkunst began.

We didn't want to develop yet another fire bowl. We wanted to create a high-quality solution that would allow users to easily upgrade an existing fire bowl. The result is our double-walled stainless steel insert for fire bowls —solidly built, versatile, and manufactured entirely in Germany.

A traditional fire bowl is transformed into a fire pit that produces significantly less smoke

The idea behind our product is intentionally simple: You place it in your existing fire bowl, add firewood, and light the fire as usual.

The real innovation lies in the double-walled construction.

Fresh air is drawn in from below between the outer and inner stainless steel walls. As it rises within the double wall, it is heated significantly by the high temperature of the fire. In the upper section, this hot air returns to the firebox.

There, it comes into contact with the rising flue gases and the parts of the wood that have not yet been completely burned. These are reignited, resulting in what is known as secondary combustion.

After the necessary warm-up phase, the result is a significantly cleaner fire with intense flames and up to 90 percent less smoke.

It is important to note that the effect does not begin immediately after lighting the fire. The stainless steel, combustion chamber, and air ducts must first reach a sufficient temperature. Depending on the type of wood, weather conditions, and the fire itself, this usually takes a little more than 15–20 minutes.

Why We Deliberately Choose 2 × 2 mm Stainless Steel

At first glance, many double-walled fireplace products look similar. What matters most, however, is what you can't see right away: the thickness of the material.

Many products available on the market are made of very thin stainless steel. Material thicknesses around 0.8 mm are common in this segment. Thicknesses greater than 1 mm are currently nonexistent—because imported goods from the Far East are designed to cut down on weight, material thickness, and workmanship and simply be inexpensive.

For us, that was out of the question.

Our double-walled insert consists of two stainless steel walls, each 2 mm thick. This means that significantly more material—twice as much—is used than in standard thin-walled designs.

You can tell that right from the moment you pick it up.

The insert doesn't look like a flimsy accessory, but rather what it's meant to be: a durable component for a high-quality fire pit.

Material thickness plays a crucial role, especially for a product that is regularly exposed to very high temperatures. In terms of heat resistance, discoloration, and usability—thinner materials are, of course, much less expensive and easier to work with, but they also need to be disposed of after a few years.

A solid construction therefore offers one thing above all else: long-lasting usability.

From the very beginning, our goal was not to build a product that would last just a few seasons, but one that would serve you for many, many years. That’s why the 2 mm stainless steel on both sides of the double wall is not just a marketing gimmick to us, but an essential part of the design.

To the best of our knowledge, our manufacturing facility is currently the only supplier in this sector that produces such a double-walled insert with a material thickness of 2 × 2 mm stainless steel. This means we offer a material thickness that is twice as thick as that of our imported competitors.

Not imported from the Far East, but manufactured in Germany

We also wanted to take a different approach to manufacturing.

A large portion of the smokeless fire pits and double-walled designs available on the European market are mass-produced in Asia. While this keeps production costs low, it often results in thinner materials and a largely standardized construction.

Our production, on the other hand, takes place entirely in Germany.

The stainless steel parts are precision-machined, assembled, and finished by hand in our stainless steel workshop. This allows us not only to determine the quality of the materials ourselves, but also to directly oversee the design and workmanship.

For us, these two things go hand in hand: If a product is meant to last for decades, quality can’t just start with the visible surface.

To the best of our current knowledge, this makes us the only German manufacturer in this industry that produces this design entirely in Germany.

For you, this also means: no anonymous imports, no changing manufacturers, and no products whose origin is difficult to trace. You receive the insert directly from our stainless steel manufacturing facility—made of top-quality stainless steel, precision-engineered, and built to provide decades of reliable service.

A solution that isn't tied to a specific fire pit

There was another aspect that was particularly important to us during development.

Many smoke-free fire pits only function as a complete, integrated system. The combustion chamber, outer wall, and airflow system are all interdependent. Therefore, if you already own a high-quality fire bowl, you usually cannot simply retrofit it with this technology.

Our double-wall insert was deliberately designed differently.

It isn't permanently attached to the fire bowl. You simply place it inside.

This ensures that your existing fire bowl remains completely intact.

If you'd like to enjoy a fire with very little smoke, use the insert. If you'd like to use your fire bowl the traditional way on another evening, simply remove it.

No drilling. No welding. No permanent changes to your fire bowl.

It is precisely this freedom that makes it so versatile.

Measuring 58 cm in diameter and 35 cm in height, it fits into many fire bowls that are large enough and is not designed exclusively for a specific Stahlkunst model.

This is another way our design differs from many existing solutions: You don't necessarily have to buy a new fire pit; instead, you can expand the fire bowl that's already in your garden.

Stainless steel, because a good product should still look good even after many years

A fire pit isn't just about function.

It is often left out on the patio or in the garden year-round, making it an integral part of the outdoor space. Its materials and design should therefore remain appealing even after many years.

The stainless steel we use is rust-resistant, weather-resistant, and designed to withstand the high temperatures of a wood fire. After a night of fire, the insert doesn’t have to be stored in the basement or garage—it can remain outside permanently. It’s a solid construction that won’t rust through and was designed specifically for long-term use.

That is exactly why we deliberately choose stainless steel and a material thickness that far exceeds what others offer.

Less smoke, without having to give up your fire pit

For us, the key question during development wasn't: How do we build yet another smoke-free fire pit?

Rather:

How can we incorporate the benefits of secondary combustion into an existing, high-quality fire pit?

Our stainless steel double-wall insert is the solution.

You get to keep the open, timeless design of your fire bowl and decide for yourself when you want to use the additional combustion technology.

At the same time, you’ll receive a product that meets our standards of quality: top-of-the-line stainless steel, exceptional material thickness, German manufacturing, and a product designed not for short-term use, but to last for decades.

The Stainless Steel Double-Wall Insert at a Glance

2 × 2 mm solid stainless steel
Two stainless steel walls, each 2 mm thick, instead of the thin-walled designs commonly found.

100% Made in Germany
Manufactured and finished in our German stainless steel factory.

Up to 90% less smoke
Preheated secondary air is used to re-burn the rising flue gases.

Versatile and flexible to use
Simply place it in a fire bowl that’s large enough and remove it when needed.

Stainless, weatherproof, and heat-resistant
Designed for long-term outdoor use.

58 cm in diameter · 35 cm high

An insert that isn't meant to replace your fire bowl—but rather to enhance it with a completely new kind of fire.