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Welder Red Seal · Question

A welder is setting up an oxy-fuel cutting torch to cut a 12 mm mild steel plate. They notice that the preheat flames are very long and feathery. What is the most likely issue with the gas mixture?

Long, feathery preheat flames indicate an excess of fuel gas, specifically acetylene, relative to the oxygen. This results in a carburizing flame which is too r

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Question: A welder is setting up an oxy-fuel cutting torch to cut a 12 mm mild steel plate. They notice that the preheat flames are very long and feathery. What is the most likely issue with the gas mixture?

Answer options: ✅ Too much acetylene for the oxygen

  • Too much oxygen for the acetylene
  • Insufficient gas pressure for both gases
  • Excessive cutting oxygen pressure

Correct answer: Too much acetylene for the oxygen

Explanation: Long, feathery preheat flames indicate an excess of fuel gas, specifically acetylene, relative to the oxygen. This results in a carburizing flame which is too rich in fuel. Reducing the acetylene flow or increasing the oxygen flow would correct this.

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