Two stainless steel rock wool sandwich panels can share the same A1 label on the RFQ and still quote 40–120% apart at the dock. The gap is not margin alone — it sits in stainless grade and surface finish, face-skin thickness, rock wool density and resin content, adhesive system, continuous-line versus hand-laid lamination, and four-side edge sealing. This module breaks the cost stack down for overseas procurement engineers, corrosion-project buyers, fire-protection subcontractors and purification GCs, then rebuilds it into a process map for audit-grade 304/316L stainless steel rock wool sandwich panels. SAMZOON, a Foshan source manufacturer, anchors the walkthrough with coil spectro control, continuous hot-press lamination, four-side sealed profiles, free pre-bid samples and South China purification project QC.