How to Weld Aluminum With an Oxy-acetylene Torch

A worker in a fabrication shop welding aluminum.
  • 1-100 hours
  • Advanced
  • 0-1,000
What You'll Need
Oxy-acetylene torch
Flat surface
Metal file
Clean rags
Bronzing rod

Oxy-acetylene torches can be used for a variety of processes, and is one of the many things that can be used to weld aluminum. Other welding techniques that are effective for aluminum include TIG (tungsten inert gas) welding and MIG (metal inert gas) welding. However, unlike these, oxy-acetylene, or arc welding, is much more widely used since it is relatively inexpensive and has equipment that is typically much more portable than TIG or MIG welding plants. So, if you're looking at a job where you need to weld aluminum, oxy-acetylene will be what you want to go with. Follow the steps below to complete this task with ease.

Step 1 - Set Up the Equipment

The oxy-acetylene torch equipment consists of two separate tanks that house the oxygen and acetylene gases respectively. After you ensure the gas valves are turned off, hook up the hoses and tighten them securely using an appropriately sized wrench. Once these are tightened, you can open the individual gas valves to check the flow.

Step 2 - Light Up the Torch

Use the regulators to adjust the flow of the gases to a starting position. This will usually require you to maximize the flow of acetylene and have the oxygen pressure set about a quarter of the way to full. You can then spark the nozzle and get the flame going. Adjust the regulator again to bring the flame to a small blue one, which will be optimal for welding use.

Step 3 - Prepare the Work Pieces

person welding

Put on appropriate protective gear such as eyeglasses and gloves before beginning this process. It is also recommended that you heat up the aluminum pieces before attempting any welding. This will help soften the aluminum and make it more amenable.

Once this is done, position the pieces to be welded as close as possible together on a flat surface, using a jig. If you feel you can get a better fit of the pieces by using a file or grinding the pieces, it is recommended you do so. Make sure the metal is clean, dry, and free of any grease or oil.

Step 4 - Introduce the Filler Rod

Welding the pieces will typically require the use of a bronzing rod. You can place this on the seam of the aluminum pieces you intend to weld and then work the torch flame on the filler by holding it a few inches above the rod. The rod will melt fairly quickly and form a metal pool to engulf the seam. The joint should have enough space to allow for the metal pool to completely cover the seam from both sides.

Step 5 - Cool Down

Finally, allow the work piece to cool down appropriately and remove any slag buildup by simply chipping away at it.