When using a circular saw, you need to be sure you're using the correct blade for the material you are cutting. Not only will you need a different blade for cutting metal than you would for cutting wood, but a metal-cutting blade should not be used in the same saw as the type used for wood.This is because a wood-cutting circular saw has an open motor housing.ou'll need different blades for different kinds of metal. You should be able to use a carbide-tipped abrasive cutoff wheel for non-ferrous metals like brass, aluminum, copper or lead. Carbide-tipped blades last up to 10 times longer than regular steel ones.