Which step follows lighting with striker in the acetylene torch start sequence?

• A. Turn on oxygen
• B. Turn on acetylene
• C. Adjust flame
• D. Turn off acetylene

Answer: (A)

After lighting with the striker, the torch needs the oxidizer to complete combustion. Opening the oxygen valve introduces the oxidizer that mixes with the acetylene to form a stable, usable flame. This should be done gradually to avoid an overly hot or unstable flame, and then you can fine-tune to a neutral flame. Without introducing oxygen first, the flame remains inefficient or dangerous; turning on acetylene after lighting would increase fuel without enough oxidizer, and turning off acetylene would extinguish the flame.