Welding with aluminum can be tricky business. It is a softer metal, with a lower melting point than many welders are familiar with. Too much heat can destroy an aluminum base, and incorrectly applied heat can cause your welding rods to become brittle. Aluminum provides an additional difficulty to the novice welder through the often non-apparent aluminum oxide coating that can build up on "dirty" aluminum. Unlike other forms of oxidation, aluminum shows no difference in appearance when it has begun to oxidize. The resulting oxidization can lead to dangerous welding accidents as much greater heat is required to work with oxidized metal.
Things You'll Need
- Welding machine (tungsten invert gas models are best suited to the welding aluminum)
- Welders gloves
- Welders mask
- Aluminum rods
- Long sleeve work clothing
- Spray bottle filled with water
- 100 percent acetone
Clean the aluminum you intend to work with. Aluminum oxide requires three times as much heat to melt, and can create a bubble around liquid aluminum beneath. When the oxide bubble finally bursts, it can cause highly viscous liquid aluminum to spill out. This is dangerous as it can ruin equipment and cause serious burns. Use 100 percent acetone to scrub down the area you will be working with. Wipe it clean, then spray it with water. Finally, use a stainless steel brush to scrub away at the area until it is highly reflective of light.
Preheat the area you will be welding for a few minutes. Do this by slowly moving your torch around the area in a circular motion at a temperature between 275 to 500 degrees Fahrenheit. This will soften the metal significantly making it much easier to work with.
Hold your aluminum rod loosely over the affected area. Do not heat the aluminum rod directly or it will become brittle and break into pieces. Instead begin to slowly scrape it across the area you are repairing and wait for it to begin to melt. If the aluminum does not melt after around 30 seconds, you should begin to increase the heat of your torch in 25 degree increments. It is best to weld aluminum at the lowest possible heat to avoid allowing the metal to become too thin or viscous.
Rub the aluminum rod around the area until the majority of the rod has melted away. If the application of the liquid aluminum was not even, you may use your stainless steel brush to smooth it out. Allow the aluminum to cool for around a minute before attempting to brush it.
Tips & Warnings
- Always wear the recommended safety equipment when welding, liquid metal can produce some of the deepest and most painful burns imaginable. Exercise caution around your workplace to ensure there are no combustible containers or flammable materials nearby.
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