Magnetic Wire

by Josehf Murchison

74K12746

Intro: Magnetic Wire

Magnetic wire is used by hobbyists and engineers for coils, inductors, transformers, and solenoids, and it is not cheap to buy at $25 to $60 dollars a pound. This is the wire I gathered in one weekend for no more cost than my time. The ten pounds of salvaged magnetic wire from 16 AWG to 34 AWG would have cost me about $300.oo dollars to buy new. And that doesn’t include the other salvaged parts like heat sinks, transformers, and other components as well as sellable scrap.

I have a homemade coil winder I use to make my own custom transformers, coils, and solenoids that I use in my projects like this auto loading coil for a coil gun, or my first coil gun where I made the step up transformer as well as the propulsion coil.

As a green project this one saves energy in the making of wire and other components as well as recycling, one of the biggest savings is to your pocket book.

STEP 1: Locating the Magnetic Wire

I get most of my magnetic wire from working TVs and Monitors, people are throwing these out because they are upgrading to the new stuff on the market. Or in the case of TV sets upgrading because the transmitters have gone digital and the old analog TVs can’t receive the signal.

The yoke ring coils as indicated in the second photo with the yellow arrows, the yoke ring coils consisting of 28 to 34 AWG wire are in the front and the back of the yoke.

The lacquered yoke coils wrapping the yokes ferrite cores indicated by the red arrow in the second photo are too hard to salvage for reuse as magnetic wire, however they bring as much as $2.50 a pound cleaned copper.

The picture tube coil indicated by the yellow arrow in the third photo, on the back of the picture tube can be wrapped in electrical tape, foil wrap, and shrink tube. The magnetic wire in this coil can be 24 to 34 AWG.

STEP 2: Gaging the Magnetic Wire

The yoke ring coils are small enough to store without transferring to a spool so I just measure them and mark them by size and approximate length.

For this you need three things, a 1 inch outside micrometer, a tape measure, and an Insulated and Bare Copper Wire Table. For my tables I use my book, “Electronics Vest Pocket Reference Book, By Harry Tomas.”

This book is a quick reference for color codes, circuit examples, formulas, and tables used by technicians and engineers alike. If you find one of these books don’t lose it I have been offered a hundred times what I paid for mine. The tables have every dimension and property of wires and other basic components you need for electronics.

This yoke coils wire is 0.0115 of an inch in diameter on top of the insulation #34 AWG wire is 0.0106 to 0.0118 of an inch on top of the insulation that makes this wire #34 AWG magnetic wire according to the Insulated and Bare Copper Wire Table.

Then using the dimensions of the coil 0.25 x 0.25 thick bundle divided by the thickness of the wire I get 484 turns on the coil.

Next from the center of the coil bundle I measure the diameter of the coil and get 5.5 inches and multiply that by Pi giving me 17.3 inches in circumference.

Multiply that by the number of turns and you get 8373.2 inches or 697.8 feet.

So I have just less than 700 feet of #34 AWG magnetic wire and I record this on the side of the coil.

STEP 3: Cleaning the Picture Tube Coil

Never hurry this, take your time cleaning the picture tube coil.

Start by finding the end of the electrical tape, this is usually near the leads of the coil and take your time exposing the ends of the leads.

Trim off the leads and expose more of the wire.

Then measure the diameter of the wire, this wire is 0.0255 inch in diameter on top of the insulation, #24 AWG is 0.0251 to 0.0268 inch in diameter on top of the insulation that makes this magnetic wire #24 AWG according to the Insulated and Bare Copper Wire Table.

Since I have the loose wire exposed I just count the number of turns coming to 120 turns on the coil.

Now I can measure the outside of the wire coil with the measuring tape and get 62 inches in circumference and multiply that by the number of turns and get a length of wire out in left field. Or I can reshape the coil round measure the diameter of the coil from the center of the bundle coming to 18 inches multiplied by Pi giving me a circumference of 56 inches. Now I multiply that by 120 turns giving me 6786 inches or 565.5 feet.

Now I can mark the coil #24 AWG and 565 feet and place the coil in storage, or I can remove the rest of the electrical tape and transfer the wire to a spool. In my case I like to make the wire easy to store so I remove the tape leaving just a tab of tape keeping the coil from unwinding until I can spool it.

STEP 4: Spooling the Picture Tube Magnetic Wire.

I save spools from fishing line, ribbons, wire and other sources just for jobs like this; I start by selecting a spool large enough to hold all the wire I am spooling. Remember the bigger the coil I am salvaging the larger the spool I need. I drape the coil of wire over the back of a chair and starting at the outside end of the wire and taking my time I start winding the wire around the spool until all the wire is on the spool. When that is done I mark the spool with the wire size and length.

STEP 5: Epilogue

This is roughly $150.oo of wire I salvaged in 1 evening while I watched TV, but that is not all I salvage. I salvage the transformers, heat sinks, wires, and components from the circuit boards. I have run across power transistors that are $85.oo each new let alone heat sinks that are impossible to find. And that is for components they still make. But most of all it saves these things from ending up in the landfills.

44 Comments

jhindustriesllc 4 years ago

Thanks, good post. I did want to mention I came across it while looking for actual “magnetic” wire, not magnet wire, which the post appears to be about. If I’m not mistaken, they are two different things. Thanks for the tips on recovering magnet wire, I needed that too :)

W.C.L 6 years ago

Thank you Josehf. I find your instructables very helpful. I am also from a household with very few assets and understand the character built as a result of 'just getting by". A strong motivation that one develops to waste not,want not. As well as to make due with what you have. I just thought I would thank you for the time that you have given to this site thru your many instructables. Time is very valuable. Especially for someone who is busy as you are. Believe me I know. So thank you for investing your time because by doing so you have saved countless others time they would have wasted. And to the critics, apparently there time is of no value because they have nothing to do but to criticize others. Pay them no mind. People always talk nonsense and criticize things they do not understand or are not willing to take the time to attempt or try. Your work is appreciated. Have a great day.

DemolisionWolf 10 years ago

I'm new to electronics, what is the difference between magnetic wire and copper wire?

Josehf Murchison 10 years ago

Copper wire is copper wire but magnetic wire is all about the insolation, with magnetic wire the insolation is designed not to be or inhibit the windings from being a capacitor.

A capacitor is a simple device; it is a conductor and an insulator.

Think of every component in a circuit as a resistor

A capacitor is an insulator with dc current, but apply a frequency to it and it is a resistor.

An inductor coil is a dead short with dc current, but apply a frequency to it and it is a resistor.

If you really pay attention to what electronic components do they are all resistors.

It is all about making sure the inductor is an inductor and not a capacitor.

By the way a very good question.

Robin- 9 years ago

Hello Josehf:

When you say "insolation" you mean "insulation." Insolation means: "solar radiation that has been received" and, as mentioned above, "magnetic wire" would imply an iron based wire, which would react to a magnetic field.

Josehf Murchison 9 years ago

Ah don't pick on words it is not that important if you get the point.

LazyH 6 years ago

that's the problem, they might not get the point. I found this article because a friend of mine asked if he is getting the right copper for a transformer because none of the wore in the tv he found would attract a magnet, and he thought magnetic wire would be magnetic, he was almost ready to use bare steel wire in a transformer because he misunderstood your answers. similarly some people might think it's ok to break open a tv picture tube outside to vent the supposed Mercury vapor you talked about, but not only is there no Mercury (it would ruin the path the electrons have to take to the screen and serve no purpose whatsoever) but they would also be very likely to injure themselves from the imploding screen if they did try it. when instructing people you need to make sure they understand what you're telling them so they don't hurt themselves, otherwise I may not have a friend anymore if he listened to you because you assume everyone will just understand even if you tell them the wrong thing.

LazyH 6 years ago

wire, not wore. time to eat my own words.

Josehf Murchison 6 years ago

I spelled insulation right in the Instructable.

I even said bare copper wire table in the Instructable.

Every one makes typeos.

Although most modern CTR's have phosphorus, some older tubes were made with mercury, although it is hard to see the tube shaped like a light bulb here has a one ounce bead of mercury in the tube. Phosphorus, mercury, or any other gas depending on the tube, you don't want to breath it in. And yes some tubes even use radioactive gas.

DemolisionWolf 10 years ago

ohh that makes sense, thank you. next question- so if i wanted to make an electromanet, using magnetic wire would be far more effective than copper wire?

Josehf Murchison 10 years ago

yes the insolation is thin on magnetic wire enabling you to get more turns in a smaller area.

just one thing with high voltages you may want fish paper between the layers it also further reduces the capacitance of the windings.

Josehf Murchison 10 years ago

Oh I forgot to mention did you notice the wires are different colors.

Red is low frequency

Gold is all frequencies

And green is audio

charlieb000 10 years ago

Actually thin is high frequency and thick is low frequency due to the skin effect.

Somebody tell those china manufacturers that the wire that they use in headphone cabling makes great litz wire and they have buyers here...

tcarney57 9 years ago

Well, wire is wire. Though the term is used here in this 'ible, there's no such thing as "magnetic" wire. What the author is showing here is called "magnet"--not "magnetic"--wire because that's one of its common uses: electromagnets. Since most copper wire is coating with some sort of insulation, and magnet wire is coated with one kind of such insulation, then it's just the same as any other wire. The lacquer-coating insulation is often more convenient for the purposes the author discusses here, but it still just insulated copper wire. Except for it bulk and sometimes the "dielectric" properties of the insulation, various kinds of plastic-insulated wire can be used for many--if not all--of the applications shown in this Instructable, including coils for RF applications.

Northrrn_Joe 8 years ago

Is there anything dangerous inside a television?
Is potentially lethal electricity still inside an unplugged TV?
If so, what precaution should be taken?

I've been wanting to try some simple DC motor experiments with my stepson but I don't want to buy special magnet wire if I don't have to.

Josehf Murchison 8 years ago

Yes high voltage can be stored in a number of places for a long time even with the TV unplugged. I short the prongs of the power cord and ground the high voltage of the flyback. The red wire that goes to the side of the picture tube. If you are working with a TV that has tubes instead of transistors you may need to short all the capacitors one at a time. If you are not sure short all the capacitors and the flyback. After that there is the gas from the picture tube if you crack or brake the tube it will suck air in first and then the gas will leak out it has mercury in it.

LazyH 6 years ago

there is no Mercury because there is no gas, it's a complete vacuum. the main concern with the picture tube is that the tube can implode quite violently if cracked and the phosphor coating can be toxic if I remember right.

MarkM196 8 years ago

I need to purchase some 14ga bare copper wire for a magnetic coil project. On eBay, there are several choices available: Round, Half Round, and square. There is also: Soft, Half Hard, and Hard. Can you help explain why some of these choices would work better than others? Thank you in advance.
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