Search "gros(se)" and "grossier".
Translate "gros/grosse" as “coarse” (e.g. sand) or “thick”/”big” depending on context.
Determine whether "grossier" is used differently and should be translated differently. E.g. does it seem to have a moral or aesthetic dimension along the lines of "vulgar"?
24r. "metal fin" vs "metal gros" translated as "fine metal" vs "coarse metal" – @ps2270 does that sound ok?
What is "coarse metal"? How many instances of "metal gros" are there?