How to Weld Aluminum With a Miller's M-25 MIG Gun
Aluminum is a soft, lightweight metal with a lower melting point than most manufacturing metals. Many welders are unfamiliar with the proper techniques for welding aluminum and end up destroying aluminum components by applying too much heat. Aluminum also offers another problem for many novice welders in the form of oxidization bubbles that can suddenly appear out of nowhere before bursting. These bubbles form a heat-resistant skin that allows the aluminum underneath to remain as liquid and hot, and when the bubbles burst, they can send molten aluminum pouring out, which is very dangerous.
Things You'll Need
- Welders gloves
- Welders mask
- Long-sleeve work clothing
- Aluminum welding rods
- Spray bottle filled with water
- 100 percent acetone
Instructions
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1
Clean the aluminum you wish to weld. Aluminum oxide is invisible to the eye, yet it requires three times more heat to melt than aluminum. To avoid dangerous oxidization bubbles, thoroughly clean any aluminum before putting heat to it. Use 100 percent acetone to scrub down the aluminum, and wipe the aluminum clean with a rag. Spritz the aluminum with water afterwards to help disperse the acetone, then take a stainless steel brush to the surface of the aluminum for a final scrubbing. The aluminum should become fairly reflective of light when it is sufficiently clean.
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2
Power on the Miller welding machine, and set the temperature somewhere between 275 and 500 degrees Fahrenheit, depending on the work you will be doing. Anything lower than 275 degrees will not sufficiently heat the aluminum, and anything above 500 degrees will melt or destroy aluminum.
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Use the MIG gun to preheat the area you will be welding. Slowly move the MIG gun around the surface of the aluminum in circular motions for 3 to 5 minutes. This will soften the aluminum significantly, which will make it more malleable and easier to weld.
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Slowly rub your aluminum welding rods against the heated surface of the aluminum. Never apply heat directly to the aluminum welding rods, or they will become brittle and shatter. After a few seconds of rubbing, the welding rods should start to liquefy. If the rods do not melt after 30 seconds, you may need to increase the temperature of the MIG gun.
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Manipulate the aluminum welding rods as though you were holding a pencil. Use slow, even motions as you "draw" the aluminum onto the work area. Continue rubbing the rods against the surface of the aluminum until most of the rod has melted away.
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Allow the aluminum to cool for a minute or two, then take your stainless steel brush to the cooling aluminum to even out the application and ensure uniform thickness.
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Tips & Warnings
Always put on appropriate welding clothes and safety equipment before using a welder. Liquid metal can cause extremely painful and severe burns. Keep your work area clean, and ensure that there are no flammable objects or combustible containers before heating up your MIG gun.
