I am by no means an expert on flares, but I was a machinist in a large heavy equipment manufacturer factory and learned a few things about leaky o-ring grooves that should apply to flares as well. Any scratch in a circular pattern will likely still seal but a vertical scratch (from inside the line to outer edge), or hairline crack in the case of a stretched metal flare, will leak no matter how hard you torque it.

1957 Chevy 3200
Daily Driver
PS, A/C, Tilt column, Rebuilt 350, Rebuilt TH350, Reupholstered Bench Seat, sound proof/insulated, LED headlights/taillights/backup lights/interior courtesy lights.
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