#004 — Thermic Lance

A steel pipe packed with iron rods and fed pure oxygen — cuts through concrete, steel, and basically anything else on Earth.

Ratings

🧪 What Is It?

A thermic lance (also called a burning bar) is a steel pipe packed tightly with thin iron or steel rods. You light one end with a torch, then feed pure oxygen through the pipe. The iron burns — not melts, burns — in the oxygen stream at roughly 4,500degF (2,500degC). At that temperature, the lance doesn't just cut steel — it cuts through concrete, rock, cast iron, and pretty much any solid material humans have ever made.

This is the same tool demolition crews use to cut apart bridges and industrial equipment. The terrifying thing is how simple it is — just iron, oxygen, and a pipe. The iron is the fuel. The oxygen makes it burn at temperatures that make an oxy-acetylene torch look like a birthday candle.

🔨 Build Steps

1. Pack the lance. Cut your iron rods or straightened coat hangers to the length of your steel pipe. Pack them tightly inside — you want the pipe as full as possible. The more iron, the more fuel, the longer the burn. A 3-foot lance packed tight will burn for about 30-60 seconds.

2. Connect the oxygen supply. Attach a hose fitting to one end of the pipe. You can weld on a fitting, use a compression fitting, or wrap the hose connection with wire and tape (not ideal but works for a demo). Connect this to your oxygen tank's regulator. Set the regulator to about 20-40 PSI to start.

3. Set up the cutting area. Place your target material (concrete block, steel plate) on a bed of sand or fire bricks. You need at least 10 feet of clear space in every direction. The slag that drips off is molten iron at 4,500degF — it will burn through almost anything it lands on.

4. Gear up. Put on welding gloves, face shield, leather apron or jacket, and closed-toe leather boots. No synthetic fabrics — they melt. This is not optional. Molten iron spatter will fly.

5. Ignite the tip. With the oxygen OFF, use your propane or oxy-acetylene torch to heat the tip of the lance until the steel pipe and iron rods are glowing bright orange. This takes 30-60 seconds of sustained heating.

6. Open the oxygen. Once the tip is glowing, slowly open the oxygen valve. The iron will catch fire immediately — you'll see a brilliant white flame and a shower of sparks. The tip temperature will jump from orange to white-hot almost instantly.

7. Cut. Press the burning tip against your target material and push slowly. The lance will bore through concrete in seconds and steel plate in a few seconds more. Move steadily — don't stay in one spot or you'll burn a hole straight down instead of cutting a line.

8. Monitor burn length. The lance consumes itself from the tip backward. When it gets within 12 inches of your hand grip, shut off the oxygen and set the lance down on the sand bed. Never hold a lance that has burned too short.

⚠️ Safety Notes

Spicy Level 5 build. Read the Safety Guide and Chemical Safety, Fire & Pyro Safety, High Voltage Safety before starting.

[!CAUTION] This operates at temperatures that will instantly ignite anything flammable. Molten slag at 4,500degF sprays in unpredictable directions. Do this outdoors on bare dirt or concrete, far from any structure. Have a fire extinguisher AND a garden hose ready. The slag can start fires 10+ feet away.

• Pure oxygen makes everything more flammable. Grease, oil, and organic material can spontaneously ignite in enriched oxygen environments. Make sure your regulator, hose, and fittings are oxygen-rated and oil-free. Never use pipe tape with PTFE on oxygen fittings.
• The lance itself is consumed during use. It gets shorter and shorter. Plan your grip position and know when to stop. If the burning front gets within arm's reach, you're already too close. Use the longest pipe practical.

🔗 See Also

• Desktop Foundry — a gentler way to melt metal, with more control
• Fresnel Lens Solar Forge — another way to achieve metal-melting temperatures from scavenged parts