A retired welder in Tacoma told me he always used a 3/8 inch gap for his first root pass.

Aaron Bell · 2026-03-31T08:05:05.512554+00:00

I was helping him clean out his shop and he pointed to an old boiler he built in 1982, saying 'that gap never failed me, even on cold steel.' I've been using a tighter fit for years, but his record made me question my setup. What's your go-to root gap for standard carbon steel plate?

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A retired welder in Tacoma told me he always used a 3/8 inch gap for his first root pass. | Boilermakers - Librear