That union steward in Gary set me straight on my prep work

Was grinding a big pressure vessel last month and this old timer walks up, watches me for a minute, points at my disc and says 'you're polishing rust, not removing it.' He was right, I was using a worn out flap wheel and just smearing the scale. Told me to switch to a 36 grit and slow down, stop rushing the pad. Made me redo a 20 foot seam that I woulda sworn was clean, and the weld came out way better. Anyone else get humbled by a guy who's been in the shop since the 80s about something you thought you had down?

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the_gray1d agoTop Commenter

Yeah, that's a solid story but I mean, he wasn't totally right about the 36 grit. If you're on a pressure vessel, 36 grit can leave deep scratches that turn into stress points later, especially on something that's gonna see high pressure cycles. I'd say step down to 50 or 60 after you knock the heavy stuff off, then hit it with a nice 120 to blend. That old timer was probably thinking about pipe work or something where they're in a hurry. Still, his point about fixing your prep before you polish stands, that's the real lesson.