Steel Surface Prep Calculator

Surface Area is the only continuous number this calculator reads, so every quantity here scales with it in lockstep -- double the area and abrasive pounds, primer gallons, labor hours, and total cost all double too. The real texture comes from the two coded selectors. Prep Level moves from SP-6 Commercial Blast (7 lb of steel grit per sq ft, a 200 sq ft/hr blast rate) up to SP-5 White Metal Blast (14 lb/sq ft, only 100 sq ft/hr) -- the strictest standard doubles abrasive consumption and blasting hours for the identical surface area, without touching primer at all -- SP-6, SP-10, and SP-5 are real named AMPP (formerly SSPC) surface preparation standards, not arbitrary labels, and each specifies its own required residual-contamination level and inspection criteria beyond just an abrasive rate.

Primer Type sets dry film thickness, coverage, and unit cost together: inorganic zinc lays down 3.5 mil at $85/gal, epoxy 5 mil at $55/gal, alkyd only 2.5 mil at $35/gal. Because effective coverage folds in each primer's transfer efficiency (60-70%), the cheapest-per-gallon alkyd also ends up cheapest overall for a given job -- and despite its thicker 5 mil film, epoxy actually comes in cheaper than zinc too: at the 5,000 sq ft default and SP-6 prep, zinc totals about $7,126 versus roughly $6,776 for epoxy, because epoxy's higher 65% transfer efficiency (versus zinc's 60%) and lower $55/gal price more than offset the thicker film. The calculator does not model containment, dust collection, or weather-hold days that field blasting schedules typically need to absorb.