A chat with an old welder about pre-heat changed my whole approach
I was working on a carbon steel header replacement last week, and the old guy running the supply house saw my setup. He said, 'Kid, your chart says 250, but that metal's been sitting in a 40-degree yard. Feel it.' I checked with a temp gun and it was 45 degrees. He told me to always check the actual metal, not just go by the book, because the soak time changes everything. I added an extra 30 minutes to my pre-heat cycle and the weld puddle looked perfect, way better flow. How do you all figure out your pre-heat times on cold material?