What is Flashback in Welding?

When gases flashback the flame regresses from outside (off of) the tip in use into the torch body itself. That flame will head to the point where the gases are mixed. The flame will continue to burn at that mixing point as long as fuel and oxygen are present and allowed to flow. Virtually all torches in flashback mode will whistle, howl, screech, etc. If the operator does NOTHING, the torch will begin to destroy itself in a matter of seconds, with the flame burning through the torch at some weak point. In addition, if unchecked, the flame may continue to migrate upstream seeking fuel/oxygen until it reaches the gas cylinder itself, at which point an explosion may occur.

What causes a flashback in welding?

Flashback can be caused by several things:

  1. Dirty or damaged gas nozzles – If the orifice of the nozzle is restricted or damaged in any way, it can cause flashback. The nozzle should be clean and free of debris, and the orifice should be clear.
  2. Leaking fittings – If any of the fittings in the gas line are loose or leaking, it can cause flashback. All fittings should be checked to make sure they are tight and not leaking before welding.
  3. Dirty gas hoses – If the gas hoses are dirty or have debris in them, it can cause flashback. The hoses should be cleaned out before welding.
  4. Incorrect gas mixture – If the gas mixture is not correct, it can cause flashback. The correct gas mixture should be used for the type of welding being done.

How to prevent flashback in welding?

There are several things that can be done to prevent flashback:

  • Use the correct gas mixture for the type of welding being done.
  • Check all fittings to make sure they are tight and not leaking.
  • Clean all gas hoses before welding.
  • Keep the torch tip clean and free of debris.
  • Replace damaged or restricted gas nozzles.

What is backfiring in welding?

Backfiring is when the torch flame goes out due to lack of oxygen.

Flashback arrestor acetylene

An acetylene welding torch is a welding torch that uses acetylene as the primary fuel. Acetylene torches are used for a variety of purposes, including soldering, brazing, and cutting metals.

What is the difference between flashback and backfire?

The difference between flashback and backfire is that flashback is when the flame regresses into the torch body, while backfire is when the flame goes out due to lack of oxygen.

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