Determine the type of metal blade you need based on the type and thickness of the metal you plan to cut. Use a blade with 24 to 32 teeth per inch for sheet metal or tubing less than 1/8 inch thick. Use 18 teeth per inch for thicker sheet metal and tubing. You can use blades with 10 to 14 teeth per inch for solid stock metals such as aluminum, copper, cast iron and steel. Unplug the machine when changing the blade.
Set the blade feed to a lower speed. Wood bandsaws normally cut at 1,000 to 3,000 feet per minute; cut metal at no more than 300 feet per minute. Many metal bandsaws have a stroke speed control device as well as a feed speed clutch. If you have a metal bandsaw, check its manual for what stroke and feed speeds it requires for different kinds of metal. You can fit some nonadjustable-speed wood bandsaws with a speed reduction device.
Place the metal you'd like to cut on the table of the bandsaw, and secure it tightly in a vice or a clamping device. Do not hand-feed metal through the blade like you can with wood can because you can more easily lose your grip on metal, potentially resulting in dangerous fly-back.
Lubricate the blade and metal with a metal-cutting lubricant if your bandsaw does not have a self-lubricating function.
Set the saw guide to an appropriate level.
Wear safety glasses and a protective shirt or coat. You can also wear safety gloves if you wish.
Feed the metal slowly and steadily through the saw., pushing it with a miter guide or wood block. Keep your fingers far away from the blade. Stop the blade, back the metal out, let it all cool down and relubricate the metal appears to have become too hot. If the teeth catch the metal too much, stop the blade, back the metal out and adjust the speed---or use a finer blade.