Hob burners black from dishwasher

Hippyhop

Morning,

I stupidly put my hob burners in the dishwasher and they have come out black.
Now I know they are aluminium and shouldn’t have gone in there. What can I do to make them sparkly again?
So angry with myself for doing it, it’s a new oven 😱
Would be so grateful for people’s tips.
Thank you x

Aylesbury_Duck

Make a paste with cream of tartar and water, to a toothpaste-type consistency. Wipe them all over and then scrub with a brush. Not a wire brush. If this doesn't work, make the paste with white vinegar instead of water.

If you're interested in how it's happened, it's because the dishwasher detergent contains alkaline phosphates. At higher pH levels, the 'weathered' aluminum surface dissolves as sodium aluminate. This reveals fresh metal underneath, which reacts with the phosphates in the water to form aluminum phosphate. Sodium aluminate reacts with sodium phosphate to form sodium aluminum phosphate. Sodium aluminum phosphates precipitate out of the water and deposit on the surface of the aluminum burners. Cream of tartar is a potassium acid salt, so it will break down the deposits.

Hippyhop

Thank you so much, I will go out today to buy the cream of tartar. Thank you

Hippyhop

Thanks so much for your help. They are looking great after I tried those things 😊

tonyh66

Aylesbury_Duck wrote: »

Make a paste with cream of tartar and water, to a toothpaste-type consistency. Wipe them all over and then scrub with a brush. Not a wire brush. If this doesn't work, make the paste with white vinegar instead of water.

If you're interested in how it's happened, it's because the dishwasher detergent contains alkaline phosphates. At higher pH levels, the 'weathered' aluminum surface dissolves as sodium aluminate. This reveals fresh metal underneath, which reacts with the phosphates in the water to form aluminum phosphate. Sodium aluminate reacts with sodium phosphate to form sodium aluminum phosphate. Sodium aluminum phosphates precipitate out of the water and deposit on the surface of the aluminum burners. Cream of tartar is a potassium acid salt, so it will break down the deposits.

you have too much time on your hands, great reply though.

Aylesbury_Duck

tonyh66 wrote: »

you have too much time on your hands, great reply though.

Thanks. I've always got time for a little household science education. I find it fascinating and hope I can make others interested in it too. It was chance conversations about things like this that led me to science many years ago. Stuff like this happens all around kitchens and bathrooms whereas a lot of kids grow up thinking science is confined to the labs at school.

There's a rather cool experiment to measure the approximate speed of light which can be done at home with a microwave and a chocolate bar...well, cool for a geek like me, anyway!

ryder72

Or you can just resign yourself to the fact that your burners are blackish and live happily in the knowledge that apart from discolouration, they are perfectly fine to go in a dishwasher.

unforeseen

Cream of tartar? Is that the stuff with capers in it? ��

Head_The_Ball

Aylesbury_Duck wrote: »

..There's a rather cool experiment to measure the approximate speed of light which can be done at home with a microwave and a chocolate bar...well, cool for a geek like me, anyway!

Please tell.

That sounds like fun.

Can I eat the chocolate afterwards?

Aylesbury_Duck

Head_The_Ball wrote: »

Please tell.

That sounds like fun.

Can I eat the chocolate afterwards?

Yes you can, once it's cooled!

Take a bar of chocolate, the flatter the better (cooking chocolate is usually nice and flat). Put it in a microwave without a turntable or if you only have a turntable model, take the plate out and turn it upside down so that it doesn't rotate. Put the chocolate bar flat on the upturned plate and run the microwave for 10 seconds. Open and check for melted spots. If there aren't any, repeat for 10 seconds until you see some melted spots.

Microwaves travel in sine waves and travel at the speed of light. Speed can be expressed as wavelength multiplied by frequency. The melted spots you will see are the points where the microwaves enter the chocolate, turn around underneath and come back up through it. The distance between two spots is therefore half a wavelength. Multiply this distance (in metres) by the frequency of the microwave, which is usually 2.45GHz but it will be confirmed on a label inside or on the back of the unit and then multiply that answer by two (because the distance is only half of one wavelength). The result will be something close to 300 million metres per second, which is very close to the speed of light.

Edited to add: Make sure you use the right units in all your calculations. Measure the distance in mm and then convert to metres. 2.45GHz is 2.45 billion Hertz and is the number of cycles the waves complete per second. You need to use Hertz in the calculation.

If it's a standard microwave, you'll probably find that the molten spots end up being about 6cm apart, which is 0.06 metres. 0.06m x 2 x 2,450,000,000Hz = 294,000,000 metres per second. The speed of light is 299,792,458 metres per second. Pretty close, and you will get closer if you are really accurate with your chocolate measurement!

shaun_from_Africa

Reminds me of a microwave experiment that I was witness to a long time ago.

I was working night shift and there was a microwave in the tearoom.
One of the other engineers told us that he had heard that if you dry a banana skin, you can smoke it and get high.
He then proceeded to put a whole banana in the oven and turn it on.

As you can imagine. A bananas pulp has a high water content (around 70%) and the banana skin is fairly watertight.
The inside of the banana obviously cooked vey quickly and turned into a napalm type of material.
This lead to a very loud pop and the whole inside of the oven getting coated in a very sticky, very hot mess.

The tip about getting the black burners back to normal is very useful though and something that I'll store aware for future reference.