Making a custom metal shape that will reduce eddy current?

[energia9]

you are welcome and looking at the diagram its a great research field. great idea.  if you do choose to make the powder techique then i would suggest you use only iron powder and no nickel in it since you want it for low alternations,    addition of nickel is good in high frequency cores.

another interresting thing to add from me,  when i experimented with iron powder i realized that i could align the particles of iron with a magnet then when the resin cured iit stayed like that.  just something to think about.

[gotoluc]

you need to experiment with the ratios, and you make a mold and just pour it in the mold

I'm sorry but I would not agree!... if the mix ratio is at a state you can pour it in the mold then you have way too much resin and you won't have good permeability.

This topic will confirm it: http://www.energeticforum.com/renewable-energy/16635-fe3o4-cores-black-iron-oxide-magnetite-knowledge-base.html

What you want is minimum resin in your mix for most permeability.

I have many years of resin work experience and I can tell you it is not as easy to work with resins than most people make it sound.
Polyester resin (aka fiberglass resin) is inexpensive but your working time can be limited by room temperature and the size of the mix. It would be best to use minimum catalyst, not warm temperature and small batch size to extend your work time. If not, your mix can start to harden while you're still trying to get an even mix and before you have a chance to pack it in your mold.
You could end up with a chunk of wasted money.

There's also Epoxy resin to consider. Three time the cost but has advantages. One is, it hardens slower than polyester so you have more working time. Another bonus is does not easily crack like polyester, which can be useful if you need it to last and be strong.
There's a special Epoxy made by Mas Epoxies that is Low Viscosity compared to regular epoxy and polyester resins.
I would recommend that as the ideal resin, since Low Viscosity will be easier to mix in so you use less resin and since it's epoxy it gives you more than double the strength and flex that polyester resin have.
I would say Low Viscosity is enough to make it the ideal choice but since you get more strength and more work time I would say it's the only way to go.

Hope this helps and wish you all the best in your experiments.

Luc

[Magluvin]

Surf board resin is very thin compared to most. It also has excellent wetting abillity. So it should be an easy mix. Like Luc says, if you want a core that is even close to what can be bought, the mix should end up like a thick putty, very dense with magnetic material. Not so thick that there is possibility of lots of air pockets.

Another idea that might work well is very thin CA (superglue) from a local hobby shop. This is on my list of things to try, as I have recovered some nice fine iron powder from a bead blaster cabinet at work using a magnet, and have the thin CA on hand.  Ill try to do a small sample to see if it works well or not. I need to do the test anyway before I waste the powder that I have. The density of the iron should prevent the CA from heating up too much and curdling/boiling as in some situations CA can do. The very thin ca has excellent wetting also. So just fill your mold with the magnetic material and apply the CA. It should seep into every nook and cranny. It just might be the new way to go.  About 10 bucks for 2oz at your local hobby shop. A bit more for ZAP brand.  Ebay also, just add shipping.

Mags

[gotoluc]

Hey Mags

one guy had a great idea at the EF topic I posted above. Use paraffin wax for experimental molds. When you heat it it's very thin and penetrates, once cold it should be had enough for experiments. When done and you want to make a change, just heat and re-mold.

Luc

[Magluvin]

Hey Mags

one guy had a great idea at the EF topic I posted above. Use paraffin wax for experimental molds. When you heat it it's very thin and penetrates, once cold it should be had enough for experiments. When done and you want to make a change, just heat and re-mold.

Luc

Hey Luc

It would be interesting to see if something like that holds together.  Sort of like pie crust dough, too much flour and it might not hold together well. But would be interesting to try. 

Mags