How Can I Remove Metal From Ceramic?

[reed201]

Hi,

 

I accidentally let a pot sit empty on the range top with the burner turned on. It probably sat there for 10 minutes or so. When I returned to the kitchen it was so hot that the pot's bottom was bowed out and it was teetering on the cooktop surface. I turned off the burner and set the pot to the side. The pot quickly cooled and the bottom was basically flat when it cooled. I hit it with the heel of my hand a couple of times to finish flattening it. I think the base of the pot is copper-over-stainless. The bottom is very thin.

 

I think the cooktop is ceramic.

 

When I removed the pot, the whole area where the pot had roasted was cloudy white. After it cooled, I worked for a couple of hours using a combination of towels, rags, a non-scratch scrubber, a Scotchbrite abrasive scrubber, Weiman's cooktop mild abrasive, Softscrub mild abrasive, and sandpaper to remove the cloudiness and most of the thin layer of metal that is fused to the ceramic cooktop. Now I'm down to the thickest part of the  deposited metal, and it's really gotten tedious. And I think that the damage I do removing the final bit might be quite visible. After taking the pictures I see I've already caused a lot of damage, but it's not too visible from a distance yet.

 

Questions

1. How the heck did metal that looks like stainless steel transfer through the copper-clad bottom of the pot to the burner? (Yes, I wiped up some reddish deposit that must have been copper too, especially where I sat the pot to cool.)

2. Do you think I can wipe on a little nitric acid to dissolve the metal and then wipe it off? I can leave the doors open to let the fumes dissipate while the reaction occurs. I suppose it would be bad to suck the fumes up through the metal range hood, right?

3. If 50% nitric acid solution is a good idea, where can I get just one ounce of it? I've seen a 500 ml bottle somewhere online, but where could I dispose of the rest? I don't want to do environmental damage.

 

Pictures attached:

The pot after a good scrubbing with Scotchbrite and Softscrub.

The cooktop with metal deposition that looks like stainless steel.

Edited November 2, 2018 by reed201

[GAHD]

kek.

Here:

Edit: as for any metal: If it liquefied once, it'll liquefy a second time. heat it up, use something to sop it up(chaulk perhaps?) then get on to polishing out the scratch damage you've caused. Edited November 3, 2018 by GAHD

[reed201]

Thanks for the great video on buffing out the scratches.

 

I'm wary of getting the cooktop that hot again, but heating it until it liquefies the metal is a good idea.

 

Chalk? I'm researching chalk but don't see why it would be good to sop up liquefied metal.

 

I really wish there was a chemical that would take the metal off without damaging the ceramic...

[GAHD]

LOL, like any acid like you said before? Neutralizing acid is as simple as mixing it with water and a base man, (always pour the concentrated stuff INTO the clear water, not the other way around). The only thing is if the acid gets on part that isn't a glass. Mercury would prob do it too, or gallium. I'm honestly wondering what kinda metal your pot's made of cause I highly doubt even an induction cooker (which wouldn't heat up stainless, the reason some stainless has a copper bottom) shouldn't actually liquefy anything outside of a low grade solder. So IDK what to tell you, some other agent is occurring.

I just said chaulk cause it would be a desiccant and break up the liquefied metal (assuming it's actually metal) with impurities allowing you to scrub it off better. whenever you get to polishing it keep in mind you're going to probably polish away some of that fancy marking paint too.

Really it depends on exactly what it is that you got stuck on there. You tried to scrub it off, no dice. Try to cook it off, try to burn it off, try to bleach it off and try to etch it off. One'll probably work. 

Edited November 3, 2018 by GAHD

[GAHD]

(paraphrasing)

Dude has a problem with a fairly expensive bit of household appliance, he asked for help. I'm offering him advice on what he can do. That simple ;)

Edited November 3, 2018 by GAHD

[reed201]

Agreed. A stove burner may get to 1000'C I'd guess, judging by the color of a hot burner, if this chart is any indication. http://www.blksmth.com/heat_colors.htm.  And the melting points of copper and stainless steel (chromium, molybdenum, and nickle) are way above that. Yeah, tin and lead would definitely melt. Scary! The pot is about 50 years old, sounds like maybe it's time to toss it. So weird.

 

I used to work on e-beam evaporators. They used an electron beam to heat a slug of metal that evaporated onto everything in the vacuum chamber. Kind of reminds me of that.

 

Thanks for the basic chemistry lesson on neutralizing an acid. Duh. I forgot.

 

Your tips could save me from replacing the cooktop ($750). I really appreciate your help!