Shielding gas is an air chemical that hinders oxygen from entering into the welding pool. The welding pool is made up of the materials you are merging and melting together. If oxygen enters into this pool, air bubbles could form, degrading the metal when cooled. The process of using welding gas consists of spraying concentrations of the gas in the area where the blowtorch is being applied. There are various gas elements that are used to protect a welding pool from oxygen. One common gas is nitrogen in its welding gas format.
Know what metal you are welding. Welders have figured out that nitrogen, as well as hydrogen, works well with stainless steels. If your metal is stainless steel, then nitrogen welding gas is a good choice.
Put on your protective gear. This includes gloves, a welding jacket and a welding mask. It is also suggested you wear a bandanna to cover any of your hair that might be sticking out.
Place your stainless steel pieces in the design you want to weld in.
Aim the extension of the gas welding canister or tank as close to the blowtorch spot as possible. Always have the extension on the can on. Do not spray the gas from its canister close to an open flame since the canisters are under pressure and could explode.
Turn on your blowtorch and begin lightly spraying the nitrogen over the stainless steel. Both the heat and the gas need to be aimed at the same location for the welding process to work. Have the extension of the nitrogen welding gas up by a 15 degree angle away from the metal.
Check frequently to see if any air bubbles are entering the melted metal. If there are, you are not applying enough nitrogen to the process.
Most welding gas canisters have an extension you can use that will help aim the gas and keep the canister away from the heat.