What is the recommended post-flow duration per 10 amps of welding current?

• A. About 5 seconds per 10 amps
• B. About 2 seconds per 10 amps
• C. About 0.5 seconds per 10 amps
• D. About 1 second per 10 amps

Answer: (D)

Post-flow duration is the time you keep the shielding gas flowing after you finish the weld to protect the freshly welded metal as it cools and solidifies. The amount of time needed grows with the heat put into the weld because hotter, more reactive weld surfaces are more prone to oxidation or contamination as they cool.

The best answer follows a practical rule of thumb: about one second of post-flow for each ten amps of welding current. This provides enough shielding for the weld to cool and stabilize without wasting gas. So, if you’re welding at 60 amps, you’d use roughly six seconds of post-flow; at 120 amps, about twelve seconds. Longer post-flow can waste gas and isn’t usually necessary for typical GTAW work, while shorter post-flow increases the risk of oxidation at higher currents.