magnetic field viewer filim

[lonelyWOLF]

interesting material magnetic field viewer film.
maybe it is helpful pi design..? also I will make rodin coil for pi..
for detailed watch this video.
http://www.youtube.com/watch?v=ZefDwDzHKLA

[Qiaozhi]

interesting material magnetic field viewer film.
maybe it is helpful pi design..? also I will make rodin coil for pi..
for detailed watch this video.
http://www.youtube.com/watch?v=ZefDwDzHKLA

Magnetic paper is only good for viewing static magnetic fields, such as those produced by a permanent magnet or (as shown in the video) a DC field from an electromagnet. You will not get any field pattern from a PI detector. The magnetic paper will also act as a target to the detector.

[Kevco]

STATIC magnetic field viewer

Thanks lonelyWOLF for posting about Magnaflux paper. Good idea, but you will need to change how you do this.....

Although Qiaozhi is correct this would not work for dynamically changing magnetic fields (such as while a PI detector is operating), it WILL work if you run a DC current through your PI coil, so the field stays static.

I remember a friend who worked for Boroughs computers, that had a liquid suspension of magnetic ferric oxide material, which you could pour on floppy discs, to actually see the individual tracks, sectors, and even the bits when viewed under a magnifying glass. Such patterns are static, and can be viewed. That liquid suspension I believe was also named "Magnaflux", and was probably by the same company that made the Magnaflux paper in the video. It came in a small metal can, like PVC pipe cement. That same liquid should be able to be used to see the magnetic field pattern of a PI coil, when it was powered by a DC current. A current limited power supply might be good to use, to power up your coil to do this.

I had tried to make some homemade magnaflux after I saw it, and I was able to make some by using fine magnetic ferric oxide powder, and mix it with a fluid carrier - like water or alcohol (I can't remember). I used it to see old Apple II floppies - with only 140k per disc, which were not high density. I had seen a recipe on making magnetic ferric oxide, by reacting steel wool with a mixture of bleach & vinegar (OUTSIDE!), which causes it to rust incredibly fast. Collect the rust powder, dry it, and bake it in an oven at high temps (? don't know the temp now), and it will turn a darker color, and become able to be attracted to a magnet. Grind the powder as fine as possible, with a mortar & pestle. That should work to view magnetic fields, if made into a fluid mix with alcohol - a cheapo homemade version of magnaflux.

If someone makes this, it might open the door to viewing coil fields, and may be able to be used by having a plastic container with this liquid, and manually moving it around to view the coil field. I may even try it, when I'm bored. It would help view the field pattern, and be able to move it to see how far the main field lobe is located (with a fixed DC current).

WARNING: I am only recalling info here, but reacting vinegar & bleach creates something called hypochlorous acid, which is a strong oxidizer (for rusting steel), and also slowly releases the odor of chlorine. Chlorine can kill, if you inhale enough, and is very irritating in lower concentrations. Don't try to do this yourself, unless you fully understand what you're doing, while doing it outside, and with a good breeze. This is NOT the same as mixing bleach with ammonia, which creates poisonous chloramines, which is even more dangerous. You have been warned!

Thanks lonelyWOLF for bringing this idea up! A good one indeed!

Kevco

[lonelyWOLF]

hi..

Although Qiaozhi is correct this would not work for dynamically changing magnetic fields (such as while a PI detector is operating),

right. but we use one-shot pulse or very low PRF (0,5-1hz) to coil ? "apply pulse and see" is not continuos pulse
Kevco.
iron whole particles into the baby oil safety way for static field viewer but slow.. other way (chemical)are dangerous

but I have another idea. is it right ?

[Kevco]

That might work, if you have a changing field (AC, or pulsed DC) on your coil, and make sure your comparator with the resistor ladder works as your want. Initially I thought you might need a diode(s) for those pen coil circuits.

If you use a gold pan, and pan down to magnetic black sand, you might be able to use that, with a DC current in the coil, to see the field. Or use a strong magnet to pick up magnetic particles from the soil. Place the dry magnetic black sand on a piece of paper, and move it above the coil to see the field. Or you could file some iron, for iron filings, and use those in place of black sand.

Best of luck!

Kevco

[Chester]

Cheap Magnetic Field Viewer

I've made a homemade magnetic viewer for viewing magnet poles by mixing drug store glycerine with steel wool. You have to take the steel wool and cut it up into little particles.

Mix the 2 in a clear glass or plastic jar and away you go.

The glycerine is about $3-7 for 16 oz at Rire-Aid drug stores. If your lucky, the container it comes in is flat sided and not too thick. It becomes your viewer. Just add the wool.

Chester