Clean all foreign material, such as rust and dirt, away from the sections of the pipes you plan to weld together.
Cut the pipes to a bevel edge with a gas-cutting torch if the pipes are not already cut.
Put on a welder's cap and helmet with a visor and filter lens and safety goggles. Looking directly at a welding arc without a filter can burn your eyes.
Align the two pipe edges with one another.
Turn on your welding torch. Place the welding torch's flame directly against the pipe's surface. Heat the pipes with the welding torch to create a puddle of melted metal on the surface connecting the two pipes. This puddle of melted metal is known as a “tack weld.”
Turn off the welding torch. Reposition the two pipes as necessary.
Turn on the welding torch and create a second tack weld in the pipes. The number of tack welds you must create to weld the two pipes together sufficiently will vary depending on the size of the pipes. For example, small pipes that are approximately ½ inch or less in diameter require only two tack welds to remain in place. Larger pipes require additional tack welds.