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Comparing Acetylene to Alternative Cutting Fuels

Acetylene has been the fuel of choice for oxy-cutting, a process where metal is cut by mixing oxygen with a gas that creates a neutral flame which then cuts through metal using a cutting torch. Metal cutting operations tend to prefer acetylene because it burns at a particularly high temperature and saves significantly on pre-heating time. This makes for a much more efficient use of time, but there are many alternative fuels that offer various advantages when compared to acetylene.

Can any alternative fuels cut more effectively than acetylene? Are there situations when acetylene is not the ideal fuel for effective cutting?

All of the alternative fuels mentioned in this article, propane, propylene, and HGX propane, are effective for cutting metal, and therefore the strengths of each fuel for a particular application are what matters the most when selecting a cutting fuel. All can cut metal, but some cut certain metals better than others and offer cost and safety advantages.

What to Consider for a Cutting Fuel

Fuel supply is one of the most important things to consider when choosing a cutting fuel since acetylene tends to be more expensive than the alternative fuels available. Some businesses may already have a supply of an alternative fuel such as propane, and they don't make a enough cuts to warrant a specific investment in another cutting fuel. Other facilities may be more concerned with safety and have therefore automatically ruled out acetylene because it tends to be a more unstable cutting fuel.

When it comes down to the bottom line on a budget, acetylene will be more expensive than the alternative fuels available, but the question remains whether a company will lose time because of the additional labor costs when cutting with an alternative fuel that dosn't pre-heat as fast as acetylene.

Do any alternative fuels burn as hot as acetylene, save on preheating time, or offer other advantages that should be taken into consideration?

Why You May or May Not Use Acetylene as a Cutting Fuel

Acetylene cuts metal at a high temperature, which makes it extremely effective for cutting thin metals with minimal distortion. However, it could warp or create spatter on thicker metals if the cutting process takes too long to penetrate the metal completely. Nevertheless, the quick pre-heating time is the decisive factor for many who select acetylene, even if it isn't always ideal for cutting thicker metals.

Safe storage and use is a major factor to consider with an unstable fuel like acetylene.

Propylene as a Cutting Fuel

Propylene produces more heat in the outer cone of the flame than propane, but it still doesn't burn as hot as acetylene, which slows down the pre-heating process. It also uses more oxygen than acetylene, which means that fuel savings need to be balanced with the cost of oxygen.

In order to achieve optimal heat flow while cutting with propylene, use an injector torch, specially designed tips, and hoses made for alternative fuels. Propylene is very effective for cutting large and thick metals, while also providing a more stable cutting fuel that can work at pressure greater than 15 psi's. Once the metal has been pre-heated, propylene creates a quick, clean cut that will often look better than metals cut with acetylene. It is also more stable than acetylene.

Propane as a Cutting Fuel

Propane doesn't burn quite as hot as propylene, which means it also takes longer for pre-heating metal. However, much like propylene, the heat is concentrated on the outer edge of the flame and more heat can be produced by using an injector torch and torch tips designed for propane cutting operations. The cuts made when using propane for oxy-cutting are cleaner than those made by acetylene and can be made just as fast after the pre-heating period.

Opinions vary on whether propane slows down the cutting process enough for it to matter significantly for a company's bottom line, especially when the lower price of propane is taken into consideration. The deciding factor with propane may be the volume of a particular cutting operation. A little extra speed for high-volume cutting may rule out propane. However, if the majority of the metal being cut is thick, propane will make a cleaner cut with less distortion. Like propylene, propane is also more stable than acetylene.

HGX Propane as a Cutting Fuel

HGX is a relatively new additive for propane that creates an alternative fuel that burns at 5400 degrees F and uses less oxygen than acetylene. This means HGX propane can pre-heat at the same rate as acetylene, which burns at 5900 degrees F, while offering all of the cost savings and safety benefits of propane or propylene.

Much like other alternative fuels, HGX propane makes a smoother, cleaner cut than acetylene, but it also requires specific components such as compatible tips, torches, and hoses. While propylene and propane are effective for cutting, HGX is the most effective replacement for acetylene because it matches the pre-heating speeds of acetylene while also offering a cleaner cut.

Propane and propylene are still excellent choices when cutting thick metals at a lower temperature, but when it comes to finding an affordable and readily available alternative to acetylene that cuts with the same speed and even greater effectiveness, HGX propane is an excellent choice.