Does Oxygen or Acetylene Light First?

We recommend closing the oxygen valve first whenever turning off an oxy-fuel torch system especially when Acetylene is fuel.

Does acetylene burn without oxygen?

Decomposition is a chemical reaction whereby acetylene breaks down into its constituent elements, carbon and hydrogen. This reaction gives out a great deal of heat, which can cause the gas to effectively ignite without the presence of air or oxygen.

Why should oxygen and acetylene lines be purged before lighting up?

Lighting and adjusting the torch (with a positive/equal pressure mixer): Separately purge both oxygen and fuel gas lines. ... Increase fuel gas flow until flame leaves end of tip and no smoke is present.