Magnetic Pottery

[c0lin]

I am a ceramicist/potter. I am planning to make a magnetic ceramic sculpture, but I am not sure how to make it magnetic. Any help would be appreciated.

The easiest way to describe what I am planning is to describe it as a bunch of fridge magnets. In fact I definitely will not make fridge magnets. But the pieces will be not more than a few centimetres on each side, and will only have to support their own weight.

I could, of course, make normal (non-magnetic) pottery, and stick a magnetic rubber strip on the back. But this won’t achieve the effect that I am after. I would rather that the pottery itself is, somehow, magnetic. I doubt that it make a difference, but the work will be curved.

I could mix some (ferrous?) material into the clay itself, or I cold embed ready-made magnet in the clay, or … well, I am open to suggestions.

The clay will be fired first to about 1,000°C, and then again to about 1,250°C. So I need to worry about whether the physical structure of any material I use can withstand these temperatures, as well as its magnetic properties. I am not worried about the magnetic properties in the kiln, but once it cools down afterwards.

All the products that I’ve looked at have a Curie temperature, and lose their magnetism, at substantially lower temperatures than those I am looking at.

If I need to magnetise it after it has been fired, how would I set about doing that. I could try to construct a Heath Robinson / Rube Goldberg contraption. Or would I need a commercial magnetiser? Or is there a place (near London) where you can rent a magnetiser for a few seconds?

As I said earlier, any help would be appreciated.

colin..

 

[sreid]

I would start with iron or low carbon steel "Filings." I believe there are also some 400 series stainless steels that have hard magnetic propertities. You can make small quantities with a grinding wheel.

Magnetizing after firing could be done with a rare earth magnet slid across the entire ceramic surface.

 

[MJR2]

Colin,

You have not really described how magnetic or what the magnetic property hopes to accomplish. That would aid in making suggestions to you.

It does appear that embedding a ceramic magnet in the pottery and then remagnetizing is the way to go. To remagnetize or simply magnetize the object with ceramic magnets you will need 7000 to 10,000 gauss.

Mike

 

[EdStainless]

Do you want the parts to be magnets, or just to be magnetic? I presume you want magnets.

Why not make the parts ceramic magnets? They would be black or dark brown, and they would have to be made from special materials, but they would be magnets.

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[sreid]

I have only one reference to this but chemistry changes to ceramic magnets start at 1080 deg C. So you might be able to embed ceramic magnets (or ceramic magnet chunks or powder) in the pottery, fire it then magnetize using a big rare earth magnet by sweeping the surface.

As a test, buy some ceramic magnets (say, ceramic 5), heat them above 450 deg C (currie temperature) then see if you can remagnetizr them using a rare earth magnet. At the surface of a RE magnet, the field strength should approach one Tesla and the ceramic magnets only need 0.3 Tesla to saturate.

 

[MJR2]

We have cast ceramic in aluminum (1220C). It is charged afterwards.

Generally it is considered to need a minimum of 7000 gauss to get the ceramic over it's knee and fully charged.

But we have as yet seen the specs for what is the goal of this magnet.

Mike