Sciencemadness Discussion Board

Clening porcelin glazed steel pot with char on bottom - suggestions for good cleaning chem?

RogueRose - 1-8-2016 at 23:24

IDK if you people know those fairly thin walled pots often used for canning or other larger uses (many are 3-6 gallon pots) but they have a black "ceramic/porcelain/enamel" with grey and white specks all over it (like a paint brush was flicked on with the grey/white paint - it actually looks kind of like the inside of an electric oven I once had).

Well I have a char ring where the burner was under the pot and it is a mix of sugar and peanut butter. It's pretty thing layer but it is a BEAR to get off.

I poured in 1/2" water and boiled for hours & scrubbed - almost nothing. I then refilled to 1/2" and added Na2CO3 (1/3 cup) and 1/4 cup borax and boiled with lid on for 3 hours then scrubbed with a steel wire brush (like used to clean car parts and such). This got of a very thin layer but it's still almost completely there.

I don't want to damage this pan as I ahve with some others so I want to ask before I add NaOH, H2SO4, vinegar (which should be fine), KOH, Ca(OH)2, oxalic acid (pure), sodium percarbonate, 35% hydroperox, ... I don't know if there is anything else that I have that may work on here or which would be best and not damage the pan.

Any suggestions?

Deathunter88 - 2-8-2016 at 06:47

If the enamel is still intact you can try H2O2 mixed with H2SO4. (Piranha solution). Make sure you have the proper safety equipment and fully research it first. Don't use it if any steel is exposed though. Here is a good video: https://www.youtube.com/watch?v=cLpSapjKcxM

wg48 - 2-8-2016 at 08:02

I pickled a metal sheet in an enamelled cast iron bath using a dilute solution of HCl (about 1%) over night. Its etched the enamel leaving it frosted. Apparently some enamels may be formulated to match the metal not necessarily for chemical resistance. I did not notice the etching until the bath was dry

Oven cleaner should be formulated not to etch the usual oven enamels though it will not remove baked on carbon.

I suggest you try any strong acid solution or alkali on a small area first. Preferable scrap most of the crude off with an an old credit card then a plastic scourer.

[Edited on 2-8-2016 by wg48]

AJKOER - 3-8-2016 at 12:31

Thin layers of carbon can be removed by heating. I accidentally discovered this by leaving a pot on the stove. Basically, C + O2 = CO2 or, limited air feed, CO.

Some pots will, however, become discolored by over heating, so not a perfect solution by all accounts.

An interesting variation would be to apply a high temperature blow torch to the offending area, which I have not tried. Note, the cost of applying said heat treatments may exceed the pot's replacement value.

Here is an idea taken from electrolysis. There may be times when carbon electrodes corrode. My sole experience is with graphite electrodes that just fall apart. Assuming someone could suggest an appropriate reaction, turn the carbon base of the offending pot into an electrode! Actually, the whole pot is wired (good for Aluminum, copper alloys, steel pots), but only the carbon coated bottom is in contact.

Actually, if someone could get this crazy idea to work, it could be cost effective and popular.:o

[Edited on 3-8-2016 by AJKOER]