What Causes the Inside of a Microwave to Crack?

Misuse

• Misusing a microwave can cause cracks in the interior. A common example of misuse is cooking non-microwavable utensils, bowls, plates or other objects. Never put objects that contain metal or are labeled as non-microwavable in the microwave; this can cause the bottom of the oven to crack, according to the USDA Food Safety and Inspection Service. Placing food consistently in the exact center of the microwave can, over time, cause the spinning plate in the oven to crack. Although these plates are made of tempered glass, heating them in the same place every time you cook can weaken the molecular structure of the glass. Always place food slightly off center to prevent this from happening.

Mishandling

• Mishandling a microwave can also cause cracks in the interior. Microwaves are relatively sturdy, but rough handling during a move or renovation can cause damage to the interior. The spinning glass plate is the most likely part to crack due to mishandling, but the other parts of the interior can suffer as well. Always handle your microwave gently. If you're transporting it in a moving truck, place it in an appropriate box with bubble wrap to avoid damage.

Dangers

• Certain dangers can arise from a microwave with a cracked interior. If the door is cracked, for example, harmful microwaves can escape during cooking. This can cause burns and long-term health problems. Major cracks in the interior of the microwave can also cause an electrical fire. Damaged microwaves usually won’t cook food properly, which presents health risks if you're cooking meat and other products that require thorough cooking.

Repair

• Some interior cracks in the microwave can be repaired while others warrant a complete replacement of the machine. A cracked spinning plate can usually be replaced by calling the manufacturer and requesting or purchasing a new one over the phone. You may be able to repair cracks in the interior using specially designed sealant, but be very careful with this procedure and consult a professional when in doubt. Certain materials may react badly with the microwaves, presenting fire and health risks. Consider replacing your damaged microwave. New microwaves are available for as low as $100.