How do self-cleaning ovens work?

I recently read a Bash quote involving a chicken and a self-cleaning oven which I suspect would be much funnier if I knew what this self-cleaning involved. So, uh, what is involved? Enthusiastic spraying of caustic cleaning agents? Oven heats up to 5000 degrees, incinerating all grime? Is it a mechanical car wash-style affair? Google seems more interested in selling me self-cleaning ovens than explaining how they work, so once again I turn to the Dope for the answer to this truly mundane and pointless question.

According to How Stuff Works, the ovens get up to around 900 degrees F and just cooks away all the crap. I guess the idea bring that if it doesn’t burn itself off at 900 degrees, then it isn’t going to burn off at a lower temp when you’re roasting a rack of lamb.

Well, howstuffworks (take with grain of salt,) seems to support the incineration theory. (Though they list temperatures of 900F/500C, not 5000 anything.) I thought that there was at least some kind of cleaning agent that was used in conjunction, but HSF seems to say there aren’t any.

Hope that helps.

There isn’t any other cleaning agent. What you are left with is a film of ash. You do have to wipe it off with a wet sponge, but that’s it.

My mum’s oven is a “self cleaning” oven. What this seems to involve is a plate of some sort of ceramic like substance bolted to the walls of the oven, leaving a gap between the wall and the plate. Apparently, getting caustic oven cleaner on them damages them.

I’m pretty sure that her oven doesn’t have this burning cycle what HSW.com talks about. There’s no button on the front of it for putting it into such a cycle manually and I’ve definitely never seen it go through such a phase (unless it does it whilst cooking food).

What exactly the plates are made of (a grey substance with white specks in it, with a sandpaper like texture) I’m not sure of.

My parents’ old 1970s style oven was a self cleaner. It got up to 900-1000 degrees for a long time (hours?). Then you just wipe away the ash.

Smelled awful, by the way.

5000° is well above the melting point of most steels. Iron melts at about 2750°; alloying it with carbon (and some other metals) reduces the melting point.

Even 900 degrees is pretty damn hot - if you put a post-1984 penny in there, it’ll melt.

That sounds like a continuous-clean oven. The ceramic plates have a catalytic coating that acts at normal cooking temperatures.

ISTR from a university lecture ~ 20 years ago that the coating was some sort of enamel which contained a catalyst. This catalyst promoted the carbonation of grease, turning it to ash at a relatively low temp.

Tell me you’re teasing me, so I don’t have to go try it.

That’s a “continuous clean” oven, not a self-cleaning oven.

GE invented the first self-cleaning oven, which uses high heat to burn off gunk. Due to either patent or cost issues, other manufacturers had to come up with other ways to offer the same thing. They covered the inside of the oven with a bumpy ceramic substance that has some sort of catalyst on it. The idea was to increase the surface area of the walls and use the catalyst to lower the burning temperature of the food on the walls, so it burns off at normal oven temperatures. See this for an explanation.

The confusion is common and encouraged by those who make continuous clean ovens, which, though better than a regular oven, do not clean as well as a true self-cleaner. GE used to call its continuous clean ovens “clean look” ovens, because they really weren’t that much cleaner than a regular oven, but they looked that way because the spills were spread around.

No, it’s true.

Post-1984 pennies are made of zinc (with a very thin coating of copper on the outside). Zinc melts at 790F.

I make no claims about the safety of doing this in your oven, though. I tried it in my fireplace.

Nope, it’s true–well, almost (wrong year). Pennies made after 1982 are composed of a zinc core with a thin copper jacket. The copper part won’t melt, but the zinc will with a melting point of around 785[sup]o[/sup] F.

Right, it’s rather cool (err…nifty) effect. The copper is too thin to maintain any shape once the zinc melts, so it just sort of disintegrates, like skin on soup.

As an ex-Sears appliance tech (altho not particularly on ovens) and who also has owned both self cleaning and continuous cleaning type ovens—here is my 2 cents.-------

Continuous cleaning depends on a catalyst to make your spills sort of look kind of normal. Sort of spreads things around so you don’t really notice. Final analysis------your oven never really looks clean. And your oven never looks terribly terrible.

Now self cleaning ovens do raise the temps to a point (think it was 800 or 900 degrees) that everything groady looking pretty much turns to dust—which dust you just kind of wipe away.

Self cleaning ovens actually have a porcelain finish (continuous cleaning has a catalyst type finish------best it ever looks is sort of OK)

An underestimated advantage of a self cleaning oven is all that extra insulation that prevents that 800 or so degrees of heat from burning your house down.

With a self cleaning oven -------you got one hell of a very well insulated oven. And that has to be a bit of a plus.

With a continuous clean oven -----you have minimal insulation. Your house can’t burn down But you will always have a kind of crappy looking oven.

There’s (I think) an easy to tell. At least of my self-cleaning oven.

On my oven, it’s a separate setting, and when the cycle starts, the oven door automatically locks…a safety feature to prevent one from inadvertently opening the door while the thing is at whatever hellish temp is incinerating the gunk.

I meant to say “There’s (I think) an easy way to tell if you have a self-cleaning oven (versus continuous clean)” …

Hope my post is clearer now.

:smack:

There is a good reason that self cleaning ovens lock pretty quickly after being turned on to the self cleaning setting.

You are talking BIG BOOM here if the door was able to be opened at temps of about 800 degrees. Oxygen rushes in to ignite.

And you may not have a house anymore–much less a clean oven.

That’s ridiculous. Yes, any unburned material inside the oven could ignite, and the heat could conceivably damage the walls surrounding the oven or you could easily burn yourself on hot parts, but an actual explosion? Preposterous.