Remove the existing grates from your grill. Most grates lift up and off the grill but refer to your owner’s manual if you have difficulty removing the old grates.
Measure the length and width of the grill grates with a measuring tape.
Purchase infrared grill replacement grates online or at a store that sells grilling accessories. Depending on the size of your existing grill, you can purchase grates that are the exact fit, grates that are slightly larger and can be cut down to size or grates that are 1 to 2 inches smaller than the existing grates.
Cut the grates down to size, if necessary, with a jigsaw equipped with a carbide-tipped blade, table saw or band saw. Measure and mark the new grates to ensure the proper length then put on safety goggles before cutting them. If you want to use heat convection, cut the grates 1 to 2 inches shorter than the original grates. Depending on which saw you are using, you may need to mount the grate in a vise or clamp to hold it in place while making the cut.
Lay the new infrared grill grates onto your grill top in the same mounting location as the old grates.