Old timer told me to always preheat with a rosebud on thick plate, I think he's wrong

This was on a job in Tacoma last month, we were fitting up 2-inch thick A36 plate. A guy with 30 years in said to use a rosebud torch for at least 15 minutes to get an even preheat. I went with my normal method, just running stringer beads with my machine set hot to build heat gradually. His way wasted a ton of gas and time. My welds passed UT just fine, no cracks. Has anyone else found the old rosebud rule to be overkill for most shop fab work?

2 comments

2 Comments

anna_green481mo ago

Yeah that "rosebud ritual" is a total gas hog for most jobs. I've seen guys do the same thing on simple brackets just because the plate is thick. Running hot stringers to build your heat works fine on A36, it's not like you're welding on some fancy alloy. If UT passed, you're good. Save the rosebud for when you actually need a controlled preheat on something that can crack.

fisher.taylor1mo ago

Ever run into that old school rule where they treat every thick plate like it's a pressure vessel? I've seen guys burn through a whole bottle on preheat for a simple shear key. Your method of running hot stringers to build heat is solid for most shop work, especially on A36. That rosebud ritual is a leftover from when codes were overly cautious and filler metals weren't as good. If your welds passed UT without preheat, you just proved the point. Save the rosebud for when you actually need a specific interpass temp on high carbon steel.