Propane torches are categorised as air-fuel torches because they use a mixture of propane gas and oxygen. This mixture, when lit, produces a clean-burning flame suitable for heating or welding purposes. If you do not weld often or are concerned with the environmental impact of your practice, propane torches can serve you well as they are inexpensive, clean-burning and recyclable.
Ensure that the torch fixture is securely attached to the propane tank. Put on your safety goggles and thick gloves.
Move the tank's fuel knob, usually located near the collar of the torch attachment, to the "Open" or "On" position. This produces a small amount of fuel in the torch's spark cup.
Hold your spark lighter near the spark cup, near the top of the torch fixture, and ignite it. A small flame should appear from the torch.
Adjust your flame size by opening or closing the tank's oxygen valve. For welding purposes, the flame should appear as a small, distinct bluish cone. A slight hissing noise should also be heard.
Touch the torch's flame to the objects you wish to weld together.
Move the flame across the edge of the metal until it liquefies. Avoid moving the flame too slowly as this will overheat the metal. Also avoid moving it too quickly, as the metal will go unheated.
Push the two metal objects together. Move the flame around the seam to create a metal bond between the objects.
Turn the tank's fuel knob to the "Closed" or "Off" position. Store your propane tank and torch safely.
Allow the weld to set and harden overnight.
Refer to any literature included with your tank for more specific instruction. Bring your used propane tanks to a registered propane recycler. Never toss them out with your household garbage.
Never use a butane lighter to spark your propane torch. Butane is highly combustible and should not be used near contained propane gas. Do not allow children or pets near your work area.