Set up a work surface large enough to hold the finished design. Protect the surface of the table if necessary, as sheet metal edges are sharp.
Make a full size pattern of your design using paper or cardboard.
Make a complete mock up of your design before laying out and cutting into the sheet metal. If your design is for a flat decorative piece like a screen or an insert, you can use newspaper or newsprint. For dimensional designs, use cardboard.
While it's not strictly necessary to make a mock up of the design, it is an excellent way to find problems with the design before cutting into expensive sheet metal
You can piece smaller pieces of cardboard together with duct tape or masking tape to get the size you need. Appliance cartons are ideal for this purpose.
Wear heavy leather work gloves to protect your hands from cuts when you place the sheet metal on the work surface. Not only can the edges of the sheet metal cut your hands, the oil used to protect the surface of the metal from rust can irritate your skin.
Lay the pattern pieces on top of the sheet metal, secure them to the surface with tape and draw the outline with a sharp transfer pencil.
Keep the transfer pencil sharp so that you have the thinnest, finest cutting line possible. You can also use a fine tipped awl, but keep it sharp by running it over a sharpening stone or nail file as needed.
Cut out the pieces using sharp metal cutting shears. A large and/or elaborate pattern may require more than1 pair of shears to cut all the pieces.
Double check your measurements before cutting. If this sheet metal fabrication is your first project, you might want to cut your pieces just a shade larger. It's a lot easier to trim or file off the excess than try to add strips to make it larger.
