Moldable Iron Powder

A long-term back-burner project just got my attention when I found out that Home Depot sells magnetic paint.
The project is a levitating globe thingie, designed as a control systems
trainer that lets the student program the control rules in C and see how different control strategies lead to different sorts of system performance.
The paint got me thinking -- if they can make latex paint with iron powder in it, can I buy some sort of plastic resin with iron powder in it and make my own custom magnetics on the cheap?
So: does anyone know of an iron-powder/epoxy (or whatever) mix out there that you can buy, or an iron powder material that you can mix with your own resin to mold soft magnetic materials out of?
I'm looking to build some cores, and maybe have some made at a low volume if the prototypes work. I do _not_ need super high permeability -- the air gap in this is so big that according to the FEA program I'm using there's not much difference between core material with a relative permeability in the hundreds vs. iron (with relative permeability in the thousands).
Thanks.
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www.wescottdesign.com

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wrote:

Interesting! What is it called, and is there a web reference?
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On Mon, 23 Nov 2009 13:55:37 -0500, PeterD wrote:

Searching on "magnetic paint" on the Home Depot or Rust-Oleum sites should get you there.
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Tim Wescott wrote:

It's either soft iron, or it needs a strong field to polarize it. How is it used? (IIRC, the permeability of ceramic magnets id low, so they support large gaps too.)
Jerry
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Jerry Avins wrote:

From what I found searching, it's soft. that is, magnets are attracted to it, but it's not attractive on its own.
Jerry
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On Mon, 23 Nov 2009 17:50:19 -0500, Jerry Avins wrote:

Right. I'm looking for an armature material for an oddball electromagnet -- big, light (well, relatively), and capable of supporting a significant AC component without wasting it all as heat.
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Tim Wescott wrote:

Don't know about the power, but I've used these people for sample cores. Fast service and good product. They might be able to find you some powder.
https://www.amidoncorp.com /
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Hi Tim, There are a lot of iron filled epoxies out there. Two names that come to mind immediately are Moglice and Devcon. I recall Dave Trumper at MIT had a nice mag-lev demo that used a photocell as feedback.
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TTim Wescott wrote:
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On Mon, 23 Nov 2009 14:52:16 -0500, jeff wrote:

Thanks Jeff. That gave me the keywords I needed.
Goodness but it's expensive stuff, at least from McMaster. Gotta think about this again, maybe.
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wrote:

Might try picking these up, too:
http://dspace.mit.edu/bitstream/handle/1721.1/13582/24130470.pdf?sequence=1 http://dspace.mit.edu/bitstream/handle/1721.1/29730/54039899.pdf?sequence=1
PDF files worth reading. (Found them using David's name, above.)
Jon
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Look for sintered metal in a magnetic material. I think some magnets are made with sintered iron.
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On Sun, 29 Nov 2009 16:06:49 -0800, Jon Kirwan

I wish this had come up 5 months ago, when I was taking down Ceromet/MPP in Anaheim, California.
I could have gotten you guys a few thousand pounds of iron powder for free.
http://metalpowderproducts.com /
If you want a few pounds..maybe I can get it from another company if I ask nice and they want a service call.....
http://www.capstan.cc/locs-cal.htm
Gunner
"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster
Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton
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I've often wished that someone would make enameled soft iron "winding" wire. Then I could reverse the process - make up an arbitrarily complex winding on a simple bobbin, then wind the iron onto the copper "toroid" (all in a single pass of course). Tony
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Tony wrote:

Why enameled? The black oxide on soft-annealed iron wire is usually sufficient insulation to suppress eddy currents.
Jerry
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Jerry Avins wrote:

Annealed oxide-coated iron wire is used by jewelers to hold assemblies together for soldering. Solder won't flow on it. https://eclient.ijsinc.com/eshop/default.aspx
Jerry
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Tim Wescott wrote:

How about a ping-pong ball into a chemical silvering mirror solution and then electroplate iron onto it in a simple ferrous plating bath?

Yes. Although the raw material when dry requires a bit of careful handling preferably in an inert atmosphere. Finely divided iron powder intended for magnetic crack detection is usually supplied as a suspension mixed in kerosene. In the air as a dust it can be pyrophoric.
It is fun to paint some on a magnetic card strip you no longer need.

You might be better off with finely ground magnetite. That is easier to handle and doesn't go woof. This stuff is in vogue these days for fancy magnetoresponsive goops in various esoteric devices. You can make it do some of the T2 type flow then rigid things with a bit of effort - except it is dirty black gunge and gets everywhere instead of a nice mirror finish like in the movie... and a bit fanciful in some articles by the proponents of the technology. eg
http://science.howstuffworks.com/liquid-body-armor2.htm
Someone like Alfa or an NDT specialist supplier will sell you the stuff but whether you will think the price is reasonable is harder to answer.
Regards, Martin Brown
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wrote:

http://www.rustoleum.com/CBGProduct.asp?pid 7, nothing came up with the suggested search terms however.
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On Sun, 29 Nov 2009 12:56:16 -0800 (PST), iman way

Fuck you.
<plink>
Gunner
"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster
Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton
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On Sun, 29 Nov 2009 13:57:42 -0800, Gunner Asch wrote:

Hell, NO! They're clearly liberals. They lollygag around the house expecting their human servants to deliver pre-chewed food to their face and schlep away their shit, while they mutilate the furniture, piss all over everything, and sneer at you.
Hope This Helps! Rich
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On Mon, 30 Nov 2009 09:48:19 -0800, Richard the Dreaded Libertarian

:LOL..
Ill have to change that sig..you make sense.
Gunner
"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster
Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton
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