Soft iron source?

hallkbrdz

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Mar 24, 2018
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Location
Edmond, OK USA
Where can I purchase soft iron bars for various motor and other related projects?

Or is this nearly impossible to just purchase in the US (seems to be from a lack of results in searches), and I should just buy mild steel and a used kiln and make my own?

For my first project I'd like to create a modern version of the Radus boots, and then go from there seeing what else is possible using flux transfer.
 
hallkbrdz said:
Where can I purchase soft iron bars for various motor and other related projects?

Or is this nearly impossible to just purchase in the US (seems to be from a lack of results in searches), and I should just buy mild steel and a used kiln and make my own?

For my first project I'd like to create a modern version of the Radus boots, and then go from there seeing what else is possible using flux transfer.

Check for engineering materials suppliers, there's probably one reasonably close to you. I've never got it in before so I've no idea how readily available it is or prices, shouldn't imagine either would be much of an issue though. Maybe search for things like "cold drawn bronze" or "acetal" if "soft iron" is proving too vague, if an online vendor is selling those kind of things they can probably get it in for you even if they don't have it listed online.
 
What is your definition of. “Soft iron”
Do you know what carbon content you need ?
Or are you litterally just needing a fully annealed steel bar stock ?
I am imagining something like the “wrought iron” bar that a traditional blacksmith or metal worker would forge to make decorative gates and lamp posts etc, ? See if you can track one of those down.
 
Magnetically soft, not physically soft. In other words, it can easily be magnetized and demagnetized very quickly to "negate" the pull of a permanent magnet with a quick pulse on a coil, like this. The material used to make transformers would be ideal, but short of tearing up old transformers, it seems to be hard to come by. I'll look some more tomorrow.

radus.jpg

And as used for these demonstration boots:

radusboot.jpg
 
Ahh, Tx core type iron.?
DDgo throws up some useful tips..
A).. Transformer cores are 3% silicon steel.
Old Microwaves are a common source (on the roadside) for transformers to repurpose !
B)
For the transformer core, you want to use steel laminations with 3% silicon for the magnetic properties. Steel sheets have a resistance to magnetic reversal, and the silicon reduces that.
.....However, you can make your own, custom, core that actually works quite well. You can buy powdered iron. Make the mold out of wax, mix the powdered iron with an epoxy resin that is about the same consistency as fiberglass resin. Make certain the particles are not clumped together and you have a good concentration of iron. Add the drops of hardener, mix well, and pour it into the mold. Next day, remove the wax.
That diy powdered iron method sounds like it could be useful !
 
Powdered iron does seem to be the way to go, and much easier to source. Plus I can mold it to the shape I need, which is nice.

:thumb:
 
I've searched for years, and it's hard to find small amounts for DIY projects. This seller on the Bay has 40 lb lots of LARGE
laminations that can be cut down to size. Cheap for the amount you get.

Laminations; https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1311&_nkw=transformer%20laminations&_sacat=0#item3430c7051f

Also on E-bay, you can get a screaming deal on a SMC (soft magnetic iron) core that weighs 20lbs for $15 -20.
SMC isn't very strong though, so it would have to be protected. (cuts like butter in a band saw though)

Micrometals; https://www.ebay.com/itm/Micrometals-Iron-Powder-Block-Core-40-Mix-12-x-3-x-2-5-21-5lbs/282910437725?hash=item41dec6b15d:g:KlwAAOSwlJlaxNxX

Don't make your own 'resin' SMC,.. I tried, and it sucks. Needs to be under tons of pressure to work very well.
(Look up SMC process.)
 
Also on E-bay, you can get a screaming deal on a SMC (soft magnetic iron) core that weighs 20lbs for $15 -20.

Thanks for the advice! I bought 5 of the SMC bars, which should be enough for my experiments with flux transfer switching. I'm curious as what percentage of the flux is still present on the low end, how fast I can switch the path back and forth, and how much heat that will generate.
 
Sounds like a lot of experimenting. :)
SMC switches very fast.

Recommend that you don't go over the tesla flux rating of the PM magnet though, or it might de-magnetize it.
(Easier to do with heat involved.)
 
IF (big IF) it can switch quick enough, I will attempt to create a motor using this technique. If not, there are some other useful items I have in mind.

The SMC bars showed up yesterday, so I can get fully involved this weekend. :D
 
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