On Sun, 20 Oct 2013 13:09:06 -0400, micky
wrote:


I had a microwave with nothing but metal walls, ceiling, and floor.
No paint at all. I don't think arcing is a problem here. He can
check further by removing the dish and the trivet and warming a cup of
water. I'll bet there will still be no arcing. Uncovering more of
the metal won't make it worse.

The walls are not hot, even when cooking, which is why one can clean a
microwave just by boiling water in it. Food dries on but does not get
"cooked on". Just cook something and then touch the wall or the the
place on the floor with no paint, and you'll see it's not hot.

Only polar molecules are heated, and I gather it's only the polar
molecules with a resonant frequency the same as the oven's. That is,
water.

But even with water and the food that contains it, the food splattered
on the walls and floor doesn't get heated.