Step 1
Coat the inside surface of the barbecue grill lid with strips of adhesive thermal insulating tape. Overlap each strip of tape by 1 inch over the last for full coverage.
Step 2
Measure all the exterior panels of the barbecue grill that can be covered. Draw shapes of the barbecue panels, with dimensions that are 1 inch larger in every direction than the panels, onto a thermal insulating blanket. Cut out the shapes.
Step 3
Assemble the panel sections so the seams are overlapping by a 1/2 inch. Use the thermal tape to secure the overlapped seams from both sides. Cut exhaust or vent holes to line up with any that you do not want blocked.
Step 4
Slide the custom-fitted thermal cover onto the barbecue once the grill has reached a desirable temperature. Lift the cover off and set it aside when you are tending to the food.