How to Weld Copper
Copper is a high-quality material with many home improvement applications, and learning how to weld it can help with all your projects involving this metal. Copper is useful because it conducts electricity and heat well. This also makes welding it harder. Heat from the welder spreads out through the metal and doesn't concentrate on the area you want to weld. The most common type of welding for copper is the manual metal arc process, but gas metal arc and gas tungsten arc are also used. You should also know when NOT to weld copper, because soldering or brazing are often better methods, depending on the type and use of the copper.
Step 1: Safety First
Welding is a hazardous activity, and all possible precautions should be taken, no matter what kind of welding is being done. Wear your safety gear, work in a clean area, make sure there is nothing flammable nearby. Especially with copper, which conducts electricity so well, you don't want to touch the metal with bare skin when using an electric arc.
Step 2: Use Proper Filler
You want the weld metal to be stronger than the base metal. When the copper alloy contains at least 70 percent copper, use 70-30 copper-nickel filler. The filler has more nickel than the base metal, making it stronger.
Step 3: Remove All Problem Substances
Grease, oil and paints can cause your weld to crack if they get mixed in. They may contain lead, phosphorous and sulfur. Make sure the copper is clean of all foreign substances before you start. Make sure you know what alloy you are dealing with. Copper-tin-zinc alloys shouldn't be welded to copper-nickel alloys.
Step 4: Use Proper Procedures
Copper welding isn't the same as steel welding. An included angle over 70 degrees allows more careful work with the welder. Prepare the metal properly, based on its thickness. A square-butt preparation is best when the metal is 3 mm or less, and a beveled preparation for thicker metal.
Step 5: Use the Right Position
Welding can be done in different positions. Down-hand, or welding on a horizontal seam, is best for copper welding. This allows for easier welding and it takes less skill to do it well. If you are assembling something that requires other positions, it is best to put together smaller sections in a way that allows down-hand welding.
Since copper is different than steel, different procedures and techniques must be used. Make sure you completely understand the ways to handle copper safely and weld it well. Learn the type of copper, the alloy, and the thickness to make sure you are using the correct method. It is easy to end up with a mess instead of the item you wanted to make. Try it on small pieces before you attempt the real job. If you do it right, your copper welding job should look good and hold well.