This depends on the intended use. Plastic blades do not rust and are an excellent choice if the work involves water. On the other hand, polished carbon steel is considered a better-constructed blade for the same purpose. The material is more durable but is prone to rust. Stainless steel is not only durable, but it is also a common choice for drywall taping compounds, scraping residues, and various other applications. Stiffer blades can also be used as paint scrapers.