How to Gas Weld Aluminum

Most types of welding use some sort of gas, but the term "gas welding" typically refers to oxy-fuel welding. This type uses a carefully controlled mixture of oxygen and some type of fuel (usually acetylene) to produce the heat needed to melt metal. The most common method of welding aluminum is tungsten inert gas (TIG), but this method is much more expensive than ordinary gas welding. However, gas welding is still widely used for repair work, especially for pipes.

Difficulty: Moderate

Instructions

1. Examine the challenges with gas welding aluminum. This metal is an extremely efficient conductor of heat, so it's easy to overheat the entire workpiece. Additionally, aluminum doesn't readily change color when it's heated.

2. Clean the workpiece. While always important for all types of welding, this is critical for aluminum. Use a solvent such as alcohol or lacquer thinner if the piece is oily, and scrub both sides of the piece with a stainless brush just before welding.

3. Subject the weld area to a carburizing flame before gas welding with aluminum. This type of flame leaves carbon deposits that will burn off as the aluminum approaches its melting temperature.

4. Choose a larger torch tip. Gas welding aluminum should use a torch tip that's one size larger than one used for steel of the same thickness. For example, sheet steel that is four hundredths of an inch thick might need a size 00 tip, so a four hundredths of an inch thick aluminum sheet should be welded with a size 0 tip.

5. Weld quickly. The key to gas welding aluminum is to avoid overheating the metal. Aluminum welds should be made as quickly as possible while still achieving an adequate flux deposit and weld penetration.

References

• rcramer.com