Aluminum flashing protects the fascia board of your home from the elements. The aluminum flashing is thin and lends itself to a variety of cutting methods. If you do not have a manual powered jump shear, you can use tin snips or a utility knife to cut the aluminum flashing. Tin snips cut through the aluminum flashing with ease, although the design of the tin snips causes the aluminum flashing to curl around the cut and cause the aluminum flashing not to sit flat; consequently it can causing voids in the seal between the aluminum flashing and the fascia board of your house.
Set up the two sawhorses five-feet apart and parallel to each other and place the four-foot by eight-foot piece of 5/8-inch plywood across the sawhorses.
Pull a length of aluminum flashing onto the 5/8-inch plywood.
Stretch the tape measure along the length of aluminum flashing and mark the length that you need to cut the aluminum flashing with the carpenter's pencil. Make a second length mark along the other edge of the aluminum flashing.
Align the straightedge with the two length marks you placed on the aluminum flashing in the last step.
Rest the blade of the utility knife on the side of the straightedge aligned with the length marks, just off the side of the aluminum flashing.
Pull the utility knife toward you while applying excessive pressure toward the surface of the 5/8-inch plywood. Make sure that you make one pass over the aluminum flashing with the utility knife.
Remove the straightedge from the surface of the aluminum flashing and pull the loose end of the aluminum flashing toward the score line until the aluminum flashing snaps.
Lightly tap the cut of the aluminum flashing with the rubber mallet to flatten the cut end of the aluminum flashing to complete the cut.