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Copper is an excellent conductor of electricity and has a high resistance to corrosion and wear. These traits also mean that you have to take extra precautions and use specific techniques when you're welding it, but luckily, our how-to guide can help!

Things You Should Know

  • Adjust the ratio of your gas and temperature. In general, copper under 2 mm needs argon gas and up to 160 A applied.
  • Preheat your copper in a furnace until it reaches your desired temperature. Then, hold your arc at 70° to create a puddle of copper.
  • Add a copper or copper alloy filler to the arc to weld the metals together. Then, let the copper cool.
Part 1
Part 1 of 3:

Taking the Proper Safety Precautions

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  1. Whenever welding takes place, you must don the proper protective gear. Safety glasses, even within a helmet, must be worn. The welding helmet is possibly the most important piece of safety equipment because it provides protection from any sparks for both your eyes and skin. It also protects from ultraviolet rays that can damage your vision.
    • A welding jacket will protect you from flash fire and electric arc.
    • Heavy, flame-resistant gloves should also be worn to protect arms and hands from burns and scratches. Choosing material such as leather will also help protect against electric shock.
    • Don’t forget to protect your feet with heavy, leather boots. Having metatarsal guards over the laces can protect your ankles and upper foot from falling objects.
  2. Welding can give off dangerous fumes. Always be sure that adequate ventilation is available, especially in confined areas. Keep exhaust near the arc while changing the filter frequently to keep fumes to a minimum.
    • If possible, use a smoke extractor welding gun. If you’re using a semi-automatic welder gun, extra equipment may be used to exhaust the fumes towards the arc.
    • An approved respirator should always be used within confined areas to protect your lungs from fumes.
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  3. Electric shock kills individuals every year. Be sure to wear insulated boots and never wear gloves with holes. Welding machinery should always be properly grounded, and equipment should be turned off when not in use.
    • To help protect yourself further, always replace repaired parts in a timely manner and only weld in dry conditions. This includes wearing dry clothing.
  4. In order to take extra precaution, consider the location of your compressed gas cylinders. They should be away from arcs and excessive heat, as well as fastened to a sturdy surface to prevent falling. The cylinders must also not be grounded to prevent electrocution.
    • Remember: Nobody regrets having fire fighting equipment. Having a fire extinguisher could save you or your family from death.
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Part 2
Part 2 of 3:

Choosing the Copper

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  1. When welding, only clean metal should be used. Do not weld materials that have been painted or previously plated.These metals can release excess fumes. If you know a metal has been in contact with a hazardous material, do not weld unless they have been properly cleaned. Hazardous materials can be life threatening and release excess fumes.
    • If you must weld a painted or plated copper, take care with ventilation. Use your respirator and weld in an open area.
  2. When welding copper, try to use oxygen-free or P-deoxidized. Oxygen-free copper will allow copper to retain the original bronze color after welding, by preventing oxidation. This alloy generally has less than 0.02% oxygen. P-deoxidized copper contains low amounts of oxygen but tends to have up to 0.05% phosphorus and 0.05% arsenic, which can release fumes. Oxygen-free copper is the most commonly available and readily weldable copper. [1]
  3. While copper alloys can be welded, each alloy will weld differently from another. An impurity can cause different relativities of thermal expansion, thermal conductivity, or electrical conductivity. Copper alloys should only be used by a more experienced welder. [2]
    • For example, look at copper-zinc alloys. Zinc reduces the weldability in copper. It also contains a low boiling temperature resulting in toxic vapors that can be produced upon welding. [3]
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Part 3
Part 3 of 3:

Welding the Copper

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  1. Depending on if you are using TIG (tungsten inert gas) or MIG (metal inert gas), and the thickness of your copper, you will need to adjust the ratio of your gas and temperature. As a general rule of thumb, copper under 2 mm should have argon gas and up to 160 A applied. [4] If the copper is thicker, you will need to adjust the gas and amp by applying helium and upping the amp. Look online or welder’s handbook to determine the best ratio for your copper.
    • If the welding isn’t going smoothly, try using 100% helium gas. It has a higher power compared to Argon, which allows for more heat to be applied to your copper. [5]
  2. Since copper has a high thermal conductivity, high heat and preheating is necessary at thicknesses of over 0.01” (2 mm). Preheating is always measured in degrees and can be anywhere from 50 degrees Fahrenheit to 752 degrees Fahrenheit (10 degrees Celsius-400 Celsius ). [6] To preheat, simply insert your copper into a furnace until the desired temperature increase has been found.
    • Preheating allows the metal to cool slower after welding which works to produce a finer weld. This also reduces the risk of cracking.
  3. Once your safety gear is on and you’re ready to go, initiate the arc. Hold the arc steady for 2-3 seconds until the puddle appears. [7] When welding with copper, the arc should be at approximately 70 degrees to the copper.
    • An arc is a shooting line of electricity created between the electrode and the material you’re welding, copper.
  4. As soon as the puddle has appeared, gently apply a small amount of filler through the arc to weld the metals together. [8] Apply the filler by gently probing it into the pudding as the arc welds the copper together. The filler will liquify and mix in with the two copper, helping the metals weld together.
    • Your choice of filler rod will be dependent upon the type of welding you are doing, however, it should always be a copper or copper alloy rod. [9]
  5. The longer your puddle is present, the more time the copper has to oxidize. This can prevent a clean weld, so move quickly to get the welding completed. [10]
  6. Cooling too fast can mean your weld will break or crack. Slowed cooling is assisted by the preheating of copper. Allowing the copper to come to a heightened temperature before welding will keep the fresh weld warm. If welding indoors, it is acceptable to let the weld air-cool if it has been preheated.
    • When welding in cold temperatures, you may to insulate your freshly welded copper to prevent it from cracking. The simplest way to slow cooling is covering the copper with a fibreglass blanket. Another method is stacking sandbags around the copper to help prevent heat loss.
    • Never splash water or ice on a weld. If you don’t have time to patiently wait for the heat to dissipate slowly, don’t weld at all.
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Expert Q&A

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  • Question
    What is the best way to weld copper?
    Jones Welding & Industrial Supply Company
    Industrial Welding Experts
    Welding can be a complex and potentially hazardous activity. The information provided here is meant to serve as a general guideline, but it is crucial to prioritize safety and consult with a qualified welding specialist or instructor if you have any doubts or concerns. Welding techniques, materials, and equipment may vary, and the proper procedures and precautions may depend on specific circumstances. Welding involves inherent risks, such as exposure to high temperatures, intense light, fumes, and electrical hazards. Therefore, it is essential to receive proper training, follow manufacturer's guidelines, and adhere to safety regulations and practices. WikiHow and Jones Welding & Industrial Supply, Inc do not assume any responsibility or liability for any injuries, damages, or losses resulting from the use or misuse of the information provided. Always seek professional advice and take appropriate precautions to ensure your safety when engaging in welding activities. You can always consult with your local welding supply store to be led into the right direction!"
    Industrial Welding Experts
    Expert Answer
    The best types of welds to use for copper are typically TIG (Tungsten Inert Gas) welding or oxy-acetylene welding. These methods allow for precise control and produce high-quality welds on copper.
  • Question
    What type of welding rod will be most effective for brass?
    Jones Welding & Industrial Supply Company
    Industrial Welding Experts
    Welding can be a complex and potentially hazardous activity. The information provided here is meant to serve as a general guideline, but it is crucial to prioritize safety and consult with a qualified welding specialist or instructor if you have any doubts or concerns. Welding techniques, materials, and equipment may vary, and the proper procedures and precautions may depend on specific circumstances. Welding involves inherent risks, such as exposure to high temperatures, intense light, fumes, and electrical hazards. Therefore, it is essential to receive proper training, follow manufacturer's guidelines, and adhere to safety regulations and practices. WikiHow and Jones Welding & Industrial Supply, Inc do not assume any responsibility or liability for any injuries, damages, or losses resulting from the use or misuse of the information provided. Always seek professional advice and take appropriate precautions to ensure your safety when engaging in welding activities. You can always consult with your local welding supply store to be led into the right direction!"
    Industrial Welding Experts
    Expert Answer
    A brass welding rod is typically the most effective, as it's specifically designed for joining brass pieces. These rods are made of a similar composition to the brass being welded, ensuring compatibility and a strong bond.
  • Question
    How do I weld a flat copper sheet?
    Community Answer
    Slow heat with a "soft" flame so you don't blow a hole through it. Brass rod works well for seams.
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      Warnings

      • Welding requires strict safety practices. When welding, there is a risk for eye and lung damage, electrocution, fire and explosion. Only weld with extreme caution. [12]
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      About This Article

      Article Summary X

      To weld copper, use clean, oxygen-free copper, which will retain its bronze color after welding, unlike copper alloys. You'll also want to use either argon or helium gas. Since copper has a high thermal conductivity, you'll need to preheat it in a furnace before you get started. When welding with copper, it's important that you wear protective gear and work in a well-ventilated area since the process releases dangerous fumes. Also, make sure you wear insulated boots and never touch live electrical parts when working with welding equipment. To learn how to weld copper pieces together safely, scroll down!

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