If you want to prolong the life of bandsaw blades used to cut metal, invest in cutting fluid. There are two kinds of fluid options, "neat" and water soluble. "Neat" is an undiluted fluid ideal for stronger metals or high-carbon steel. Water soluble can be used for softer metals and steel with low carbon content. The idea behind cutting fluid is to keep the temperature of your cutting surface low, so don't skimp on the fluid. Heating up your bandsaw blades will shorten their lifespan over time.