Metallurgy question (oven rusting)

[Houses4Rent]

Hi

I just noticed that my oven in my tenanted flat is starting to rust badly. See pictures.

I suspect that tenant must have used some cleaning agent/chemical which accelerated that or even started it. The current tenants do not know and it might have been the tenants before them last year too.
Its 3.5 years old ad should not rust that badly. Any idea how to stop that?
Bear in mind that any treatment must be food save and withstand oven temperatures.

[AndyD]

The rust is normal if the coating failed, the question is what has caused the deterioration of the protective coating. Ovens are usually enamel coated which is heat proof, acid resistant, moisture resistant and impervious to cleaning agents. The damage to the enamel coating is extensive and I doubt it's financially viable to recoat unless it was a particularly expensive oven.

TBH I've no idea what could have caused that kinda damage in a 3 year period. Given that the roof of the oven looks equally as bad as the base I'm not sure it's tenant damage. Usually if they'd spilt or used something highly caustic the damage would be mainly on the base or if they damaged the coating with mechanical scraping then the damage would be more pronounced in areas where they'd be more likely to clean and less in areas like under the elements where you wouldn't be able to access with a scraper. The damage appears to follow the lines of the elements which suggests maybe heat damage so I wouldn't rule out the possibility of substandard manufacturing. What make is the oven? Have a look on hellopeter or do a general google to see if other customers have had quality complaints for similar ovens.

[Houses4Rent]

Thanks AndyD. Me thinks the white stuff on the "ceiling" of the oven must be a residue of whatever was used. I should have touched it to see if it is indeed topical or has eaten into the coating. Its less under the element on the ceiling as either it was not applied there or the heat burnt it off. It looks like a sprayed in substance. The worst spots are around the element cover at the bottom front where the oven door hinges are. You can see my thumb lifting the cover on the middle picture.

I agree its not mechanical damage. Does any chemical fundi have any idea what chemical substance can possibly eat into enamel? I once saw on the net that baking soda and water causes some chemical reaction to make cleaning of baked in/burned on stuff so much easier which I might have told a tenant. I never tried it myself as our gear never has "baked in" grimme. Can baking soda do that? I was useless in Chemicals at school so I have no idea.

Its a entry level Defy 600U so re-coating is not viable.

[AndyD]

I'm not any kinda chemical expert but I think enamel used to be a porcelain coating that was fired using high temperatures similar to the glaze coating used on pottery but nowadays gets used as a term that's widely used to describe a multitude of paint-on resin type coatings. As far as I know genuine fired enamel is impervious to all cleaning chemicals including baking soda and acids like lemon juice and vinegar. It's extremely brittle like glass so damage to enamel is usually in the form of chips where its received a sharp impact and I'd guess whilst using a hostile scourer could take the shine off it I don't think it would penetrate it entirely allowing the steel substrate to corrode.

Looking at a defy catalogue it appears they have different types of enamel coatings across their range of cooking equipment. Vitreous enamel is genuine fired enamel but some of their ovens have something they call 'easy-clean enamel'. Whether this is a genuine vitreous type enamel or actually some kind of resin based paint I don't know.

If it's an entry level Defy then I'd very much doubt it's worth recoating because I'd guess the oven would need completely disassembling and rebuilding in order to do it. Did you email the photos to Defy for comment? I'd be interested to hear what their take on it may be.

[Houses4Rent]

Good point. I just send pics off to my management contact at Defy and see what they say, but I doubt they will spend time on that.