Why Does My Copper Lantern Get Soot?

Nothing is more beautiful than a new copper lantern when it is first installed. Except maybe the natural patina copper that develops as lanterns are naturally exposed to weather.

But why do some copper lanterns develop problems with black soot? This is sometimes referred to as “sooting”.

If you see soot on your lantern, that’s a good sign there may be a problem. And while it’s easy to blame the lantern design when this problem occurs, normally there are several factors that lead to incomplete combustion and in most cases it’s not actually the lantern!

Read this guide to help you identify the problem and keep your lanterns looking and functioning great.

Potential Causes of Black Soot on Propane Lanterns:

• Low Quality Propane or Contaminated Fuel
• Incomplete Combustion
• Clogged Orifices or Particles in Burner
• Clogged Air Vents
• Improper Flame Adjustment

Copper gas lanterns can be powered by natural gas or propane.

Generally speaking, lanterns using natural gas don’t have issues with soot. That’s because natural gas is typically provided by a highly regulated provider and has an endless, streaming supply.

However, our customers who use propane to fuel their lanterns sometimes call asking why their lanterns accumulate soot and what can be done to prevent this.

Propane powered lanterns can often develop sooting as a result of any combination of these factors:

• The quality of the propane being used
• The amount of propane in the tank
• Dirt / debris which accumulates inside propane tanks and comes through the line when they get close to empty
• Incorrect pressure in the propane lines

In other words, propane that’s coming from a nearly empty tank, low-quality propane, or propane that’s not being pumped in at the ideal pressure levels can lead to flames that burn darker and create black smoke. This leads to soot.

If you have propane fuel and are experience sooting, please consider the following remedies:

• Talk to your propane provider. Ask about the quality of the fuel, levels of fuel in the tank, and the pressure.
• Check your pressure – The gas pressure delivered at your burner assembly should be about 1/2 PSI or 14” WC (inches of water column) as measured by a manometer.

Irregular or fluctuating gas pressure can disrupt the fuel-to-air ratio, leading to inefficient combustion. Regularly monitor the gas pressure and consult a technician or plumber if you suspect any problems. Pressure that is either too high or too low can result in an improper burn.

What is the optimal recommendation for Gas Pressure?

The gas pressure delivered at your burner assembly should be about 1/2 PSI or 14” WC (inches of water column) as measured by a manometer.

Incomplete combustion is a direct cause of black sooting.

When propane doesn’t burn completely, it releases soot particles in the air, settling on the glass, sides and top of the fixture.

If all of the fuel is being burned, your lantern flame will be a bright blue at the tips.

If part of the fuel is not being burned, it’s more orange and creates black smoke. This leads to sooting.

Understanding the components and mechanics of a propane lantern will help pinpoint the causes of black soot.

Insufficient oxygen supply to the combustion process can lead to incomplete burning, resulting in soot formation. Ensure that your lantern’s ventilation is not obstructed, and that proper airflow exists for optimal combustion.

Lanterns need a good supply of air to ventilate and support clean burning.

Unfortunately, bugs and spiders are attracted to lights and often crawl into lanterns to make nests or are simply burned by the heat and die.

The resulting debris can clog the tips of your flame or block the ventilation as designed for your lantern.

Over time, debris, dust, or spider webs can accumulate on the burner or orifices, disrupting the gas flow and affecting combustion and cause propane burner black soot.

Regular cleaning and maintenance of these components can help prevent soot buildup.

Lanterns need a good supply of air to ventilate and support clean burning.

The bottom portion of the flame in a propane lantern should burn blue, indicating complete combustion. If the flame appears yellow or orange, it signifies an improper fuel-to-air ratio, which can contribute to soot production.

Gently cleaning the tip of your lantern will remove clogs and keep it burning properly as well as maintaining good air flow, and the proper propane quality and pressure.

To minimize or eliminate black soot from your propane lantern, consider implementing the following preventive measures:

• Clean the burner, orifices, and other components periodically to remove dirt, debris, and soot residues. This helps maintain optimal combustion efficiency.

• Ensure adequate airflow by keeping air vents and chimneys clear from obstructions. Regularly inspect and clean and maintain these areas to prevent soot buildup and other combustion byproducts.

• Check gas pressure and maintain 14”WC. Aim for a blue flame to ensure complete combustion and minimize soot particles.

• Source propane from reputable suppliers to ensure high-quality fuel free from contaminants. Talk to your propane provider to address fuel supply and quality. This will contribute to cleaner and more efficient combustion.

Each hand-crafted Flambeaux lantern is designed to give you years of low-maintenance enjoyment. If you see signs of soot problems, we hope these steps will help you remedy the issue, so you enjoy your lanterns for many years to come!