Gas welding and cutting equipment

Gas Welding, Flogas Butane and Propane Information LPG is sold commerciallsy as propane and butane it is a hydrocarbon gas that forms a liquid at normal temperatures when pressure is applied to it, the pressure inside the cylinder is 7-8 bar for propane and 1-2 bar for butane at normal temperatures. When a cylinder valve is opened, gas flows out at these pressures and some of the liquid turns to gas to replace it. However, these pressures are usually too high to be fed directly to appliances, so a regulator has to be fitted to reduce and control the pressure. Most LPG appliances operate at high pressures (0.35 to 2 bar) since this gives the hot compact flames required for torches, lights and portable heating equipment.

Should you use Butane or propane for your application?

Both gas welding gases burn clearly and have a high calorific value, giving a similar flame shape and heat output.

The main differences between Butane and Propane
As gas welding is drawn off from the cylinder and liquid turns back into gas, the liquid cools down causing the rate of change from liquid to gas to slow down. This effect is particularly marked for butane which will not turn from liquid to a gas below 0oC, so that on cold days or when the gas is being withdrawn at a high rate, the liquid gets so cold that it delivers very low amounts of gas, or indeed no gas at all. So as a result butane tends to be used for low pressure domestic appliances indoors, or outdoors in the summer only. Propane continues to turn from liquid to gas at much low temperatures than butane and thus gives a high pressure of gas on the coldest of days. Although propane cylinders can be used indoors on a temporary basis, they should not be stored indoors because of the higher pressures in them.