How to make a magnetic field viewer

[bbsailor]

The link below will show you how to make a magnetic field viewer using baby oil and very fine steel wool.

YouTube- Magnetic field viewer

You may find this useful when experimenting with new pickup designs or when copying an old favorite pickup.

Paint one side of the baby oil bottle white so that you can photograph the way iron filings arrange themselves when near a magnetic field. Choose a baby oil brand that comes in a clear plastic bottle with a removeable label.

Joseph Rogowski

[David Schwab]

A trick I've done a few times is to put the pickup into a zip lock plastic bag, and then sprinkle iron filings over the front of the pickup. Not only can you see the field, but you see it in 3D!

When you are done just wipe off the filings, and then you can turn the bag inside out so you don't get any mess on the pickups.

[belwar]

I think what could be more useful would be to tape a piece of 3/16 plexi on top of the pickup, then put it in the bag.. That would let you see whats going on at string level! :>

[Beef Coon]

An oldie, but interesting.

Anyone use something like this or the magnetic viewing film?

I've yet to, but I'm going to try the oil in a bottle, maybe with a concave bottle to try and get the oil and steel around the pickup more.

[jason lollar]

the magnetic viewing film you can get at any magnet supply place is really cheap and works well

[Mike Sulzer]

I think what could be more useful would be to tape a piece of 3/16 plexi on top of the pickup, then put it in the bag.. That would let you see whats going on at string level! :>

And since it does not matter what happens to the permanent field where the string is not, a measurement with a meter where the string is can be the best of all.

[jason lollar]

it only matters where the string is not if you are checking for errors or inconsistancies like if you use pre charged magnets- you could have an uncharged magnet or a reversed magnet or you could have a magnet that doesnt take a charge properly among other things

[Mike Sulzer]

But won't all those things result in the wrong field where the string goes, a field error you can measure with the meter?

it only matters where the string is not if you are checking for errors or inconsistancies like if you use pre charged magnets- you could have an uncharged magnet or a reversed magnet or you could have a magnet that doesnt take a charge properly among other things

[Mark Hammer]

What about one of those Wooly Willy things, where you can draw eyebrows and beards on the face with the iron filings encased in plastic and an external magnet? Those should be available in any novelty or toy shop.

[jason lollar]

a gauss meter would certainly show it but how many hobbiests or even many pros have a gauss meter? a square of film about 3.5 X 3.5 inches is only a couple bucks depending on where you buy it
I like the woolly willy thing too- thats $2, i can hear it now- do you have a wooly willy???

[Mark Hammer]

Why yes. Here, let me just shake it for a bit before I show it to you!

On a more informative note, although cheap, widely available, effort-saving, and amenable to hours of grade 8 locker-room-innuendo fun, I think the baby oil container with the filings (which might be more easily obtained by purchasing a Wooly Willy, and emptying the contents into the baby-oil container) has the advantage of being able to demonstrate fields in 3-D, something that Willy with the playoff beard can't do very well. But as a quick and dirty substitute, it'll work.

[Joe Gwinn]

I used to make my own magnetic developer, to see the data tracks on magnetic tape. This was in the 1970s.

For magnetic tape, the developer was alcohol with a pinch of electrolytic iron dust. One stirred the developer, dipped the tape in the developer, and laid the tape out to dry, magnetic side up. When the tape was dry, roll some Magic tape onto the tape, peel it up, and put it down onto paper. The iron dust held by the magnetic tape's fields sticks to the Magic tape's adhesive, and is transferred to the paper. This yields very clear pictures of the data tracks. If the bits per inch is low enough, one can see the individual bits.

For pickups and their fields, I'd put some iron dust in heavy mineral oil, all in a freezer ziploc bag.

https://wardsci.com/store/catalog/pr..._number=207000

https://shop.chemicalstore.com/navig...ID=&id=IRON325

https://shop.chemicalstore.com/navig...ID=&id=IRON100

One can also get iron filings in bulk, but the particles are fairly coarse.

iron filings in Lab Chemicals | eBay

The sheet-metal filings may consist of little slivers, versus roundish particles.

[kayakerca]

I am obviously way too new and way to much a hobbyist for this. So, at the risk of having my ass kicked to the curb for my limited capacity to understand even the most rudimentary aspects of the physics of pickups, to me, the idea that a oil bottle with metal filings or a film strip could be the basis for measuring the magnetic strength of magnets to produce consistent reproducible outcomes in pickups seems ludicrous to me. Unless of course, the notion of types of magnets and their respective characteristics and strength has virtually insignificant impact on the tone or output of a pickup. I do know from my limited experience that if you run a "so called" vintage staggered Strat style pickup between neo's to magnetize them, you will have the A and B pole pieces will be at best 80% of the gauss levels of the E, D, G and E which will seem to be screaming relatively when you plug it in and have at it. If you feel this differential negatively impacts the tone and output of your pickup, no bottle of filings or magnetic film is going to see you through to a more balanced result. In my crazed, uninformed, newbie, hobbyist opinion anyway. . . And yes, I use a gauss meter and spend a lot of time trying to balance the levels on the individual rod magnets.

I must be missing the humour of everything in this thread or just had and extra glass of wine with my BBQ'd chicken this evening.

[Joe Gwinn]

The iron dust in oil is a way to view the fields, and not to measure them.

[kayakerca]

The iron dust in oil is a way to view the fields, and not to measure them.

OK, I see. It goes without saying that my physics knowledge is way too rudimentary to understand how I might incorporate the "visualization" of the shape of the magnetic field into the simplistic pickup winding I'm capable of.