Cast iron that crumbles like cookies?

If you ever see the window sash weights in an old house (pre-1930), you'll see a lot of iron like that. They were the dregs from a cupola. When they got down to something that was as much slag as iron, they poured it into molds for things that sold cheap, that didn't need any strength, and that no one would see.

The item you're talking about is a little small for that, but it probably was something similar.

Possibly ferrite? Gerry :-)} London, Canada

Its probably is (was) an incredibly rare ancient coin, worth incalculabe amounts of money. ...Or ot was, anyway.

Andrew VK3BFA

Is it possible it may have gone through a fire? I seem to recall that heat made certain types more brittle, but I don't recall if that was semi-permanent damage, or only while hot.

Would it be possible that the ring was a core from a transformer, and didn't need to be particularly strong?

--Glenn Lyford

It is almost certainly suffering from graphitic corrosion.

Probably an iron powder or ferrite toroid, a lot of them are used on computer equipment to reduce EMI. I've seen rings about that size used on the line cords, usually each side is looped through the core. They're very brittle, like ceramic or glass. They're basically powder that's pressed and sintered, no real strength required other than to hold wraps of wire.

Stan

What did the broken surface look like?

Mark Rand RTFM

This one was not brittle. Think about the toughest, strongest cookie that you ever handled, that's what it is like. I do not think that it had an electrical purpose.

Light greay and extremely grainy. I kept the pieces, just in case.

Is it magnetic? I see ring magnets stuck on some of our storage racks at the plant. I don't know where they came from. Two I do know about came from a microwave oven I scrapped out. They were on the magnetron.

Paul

Do you have a camera with a macro lens? If so, stick something into the photo for scale, and post it. I'd like to take a look, as I'm sure others would.

yes, it is magnetic.

I was going to say that too. There's been an attack of this in 30 year and older pipework carrying cooling water in UK industrial plant.

I would guess it's ferrite too. But if it's some weird kind of corrosion, I'd be very interested to see a picture.

Chris

as in a magnet will stick to it? or as in it will stick to other iron things?

Thank You, Randy

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