The choice of material directly impacts the finish and longevity. Stainless steel blades are the industry standard for professional finishing because they are rust-resistant and do not leave dark 'burn' marks on light-colored plaster. For heavy-duty masonry or base coats, high-carbon steel is preferred for its superior rigidity and wear resistance, though it requires more maintenance to prevent corrosion. For specialized applications like Venetian plaster, look for mirror-polished stainless steel to achieve a high-gloss effect.