To test microwave safety
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To test microwave safety
Ability to go from the dishwasher to the microwave. Metal overglazes should never go in the microwave, so it is a good idea to keep them off mugs and other dinnerware items. Other than that, the problem with microwaves is if there is any water trapped inside the clay, it will expand in the microwave and cause the piece to crack. Low fire clays are porous by nature, and always problematic in the microwave. If your glaze is fit very tightly (can withstand the thermal shock test with no crazing), then the glaze may prevent water from getting into the clay, and this will be ok in the microwave. High fire clays should be fired to vitrification to keep water out. (See Tip 17 for more information about vitrification.)
To test microwave safety, take a piece (such as a mug or bowl) and immerse in a pan of water. Bring the water to a boil, then simmer for a few hours. This will allow the piece to absorb water. Then put the piece in the microwave. (The piece should be empty, and you should also put a separate mug of water in the microwave to protect the microwave.) Heat the microwave on high in 10 second increments. After each 10 seconds, carefully touch the piece to see if it is hot. If it has absorbed water, it will heat up. This tells you the piece is not dishwasher safe. You can stop the test when the water in the second mug is boiling.
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| Lynne Christen |
