Anything to Worry about

[BertiWooster]

I bought a microwave oven recently .

I have noticed that on the inside of the glass ( athough it doesn't sound like glass when you tap it ) of the door , there are a number of little ' bumps' for want of a better word to describe them .

I'll try and describe them
Imagine holding up a piece of flat plastic ( as in from a plastic bag ) in front of you . then ask some one to slightly press against the plastic from the other side , with say the head of a matchstick .
The shape that you can see from your side where the matchstick is pressing against the plastic ; is what i'm attempting to describe .
You can of course feel the bumps when you run your finger over them .

Is this a fault in the glass , which would mean it is unsafe to continue using the microwave .

The make is DeLonghi

[Ethel]

My microwave isn't a DeLonghi but has bumpy glass on the inside of the door.

[heathfield]

It's possible that these are points where the glass plate has been supported when it was made, or when it was later heat-treated to turn it into safety glass. I wouldn't worry about it.

[BertiWooster]

Thanks both

Incidentally , out of interest - what is the material use for the ' glass ' in the door .
It does not sound like glass when you tap it

[heathfield]

The glass has been heat-treated to make it safety glass. If it breaks it will shatter into small fragments that can be safely handled, just like a car windscreen. It's thicker, and is around 5 times stronger than ordinary window glass. Because of this, tapping it with a coin can give a duller sound than ordinary window glass. Compare the sound to that produced from the glass in a car window, which has also been heat-treated. It will be much the same.