Moldable Iron Powder

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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Engineering is the art of making what you want from things you can get.

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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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in the 80's i did some casting using polyester resin. i was hired to make reproductions of the ornaments on the cast iron buildings in soho, new york city. i was kinda making it up as i went so i have no idea of the longevity of the stuff i made. i mixed iron powder into the resin before adding the hardener. the finished castings *actually DID look* like cast iron, i was amazed. they even rusted. thing is the iron powder is heavy and would settle to the bottom of the casting if you had a long curing time. i mean, not all of it, but it generally tended to start settling to the bottom, even in the mixing bucket, and even with heavy doses of "thixotropic powder" etc. but it was cool. and they did look like cast iron. i never thought to touch a magnet to them, i'd bet they were magnetic. i got the iron powder from some sort of scientific materials supply house, but i bet you could probably find a place that sells it much cheaper. i'm sure there must be lots of information out there about adding metal powders to resin castings. in my case, you're not supposed to use polyester resin to do castings, it heats up and i think i've heard it can even catch fire. i fudged it so i opened the molds when the resin was cured enough to hold it's shape but before they got too hot. i worked in fiberglass mat/fibers before closing the mold (polyester is brittle and would snap like ice if you don't have some sort of reinforcing material in it.) when i was in college ('78~'82) there was a guy there who was making larger than life size castings (of human figures) in polyester that had (lots) of bronze powder mixed in. i think they called it "cultured bronze". looked, more or less, like bronze. no idea there again of the longevity. i'd think there'd be no problem mixing in iron powder. (but then again i don't really know you're trying to do, i'd imagine if you were trying to cast lucite ALL the iron would settle to the bottom before it cured.) good luck. let's see some pics. ("cores", huh?)
b.w.
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If you buy casting resin, rather than laminating resin, you can cast thick sections without it getting too hot. You also can reduce the accelerator ("catalyst") to keep it cooler but that's risky business, because, if you go below the tolerable threshhold, the resin won't cure hard at all.
Casting resin is widely available from resin suppliers. It's usually much clearer than laminating resin.
Iron powder has been used to fill epoxy for making short-run forming dies. There have been entire books published about using filled epoxies (aluminum-filled, mostly, but also stone aggregate and iron) for dies and similar applications, but I haven't read one since around 1980, so I don't know what's current.
--
Ed Huntress


> when i was in college ('78~'82) there was a guy there who was making
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wrote:

Not exactly iron powder, but you can buy a 10lb bag of #7 steel shot for $21.99.
http://www.midwayusa.com/viewproduct/?productnumberE9705
Finer steel shot is used in shotblasting (like sandblasting). There are many suppliers, don't know what a bag of that goes for. Google and a couple of phone calls might be enlightening.
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Tim Wescott wrote:

Ferrite powder is manufactured (it's a component of copier toner, among other things). You might call Fair-Rite and see if they can sample you a bottle. Failing a commercial source, fabricate a ball mill and grind some yourself. Without knowing the magnetic requirements, I cannot say if ferrite will work for you.
Kevin Gallimore
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I dunno about the ability to meet your requirements, but there are iron powders available for various uses, from toys (Etch-A-Sketch), to industrial uses.. electromagnetic clutches/brakes for machines. These examples are moderately coarse powders.
Very fine iron/steel particles are a byproduct of etching/cleaning or pickling steel products in manufacturing. The steel parts are pickled in various acids, and the particles which are suspended in the liquids are then filtered to remove the particles from the acids. The result is a mud/clay-like material that is used to manufacture other products, including iron composition cores for certain magnetic properties.
I don't have any sources to recommend.
--
WB
.........
metalworking projects
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The finest iron powders are called "carbonyl iron" (http://en.wikipedia.org/wiki/Carbonyl_iron ).
Googling for carbonyl iron brought up this supplier: <http://www.chemicalstore.com/navigation/detail.asp?id=IRON100 .
Joe Gwinn

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Wild_Bill wrote:

Many years ago, the ferrite factory for which I worked used oxide from the steel mills as a raw material. I was told there were mountains of the stuff in West Virginia. To be usable for magnetics, the oxide would have to be fired in a cycle that included high temperatures and witchcraft.
Kevin Gallimore
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Zone refine. Melted in a magnetic field and the field is moved slowly towards an end - moving impurities with it.
Expensive refining but quality product. Similar to that of a semiconductor process. Likely from the ferrite business.
Martin
axolotl wrote:

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    --Hey speaking of doing stuff with metal powders have you seen Bathsheba's process description yet? http://www.bathsheba.com/sculpt/process/
--
"Steamboat Ed" Haas : Currently broke and
Hacking the Trailing Edge! : looking for a job...
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and a further reply - iron powders are used in spray-metal applications but at a price
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