About welding gasses

Reactive Gases:

The most often used fuel gas for gas welding and gas cutting is acetylene.
Because acetylene is so widely used, the terms “oxyacetylene welding” and “oxyacetylene cutting” are frequently used in place of “gas welding” and “gas cutting.”

Acetylene burns at a temperature between 3200 °C and 3500 °C (5800 °F and 6300 °F) when mixed with oxygen.

Comparing acetylene to other fuels, its high cost is its biggest drawback.
Additionally, acetylene is unstable at pressures greater than 33 feet (10 meters) underwater, making it unsuitable for underwater welding or cutting.
The recommended gas for underwater welding and cutting is hydrogen.

Acetylene is kept in special cylinders since it is unstable over 2.07 bar (30 PSI) pressure and may explode.

Oxy-propane is commonly used for cutting metals because it does not generate high temperatures like oxyacetylene, and therefore is not typically used for welding. However, oxy-propane cuts faster than oxyacetylene, and the cut edge is much cleaner than acetylene, which helps with heating and bending.

Propane gas is preferred for the heating and bending process. Propane is cheaper than acetylene and readily available. That is why oxy-propane is often used for scrap cutting. When mixed with oxygen, the maximum propane flame temperature is 2822°C (5112°F). For oxy-propane, a standard oxytorch can be used. However, it is not recommended. A special propane oxy torch is usually used. This is easier to light than an acetylene oxy torch and less likely to blow up.