Parts, & Parts Suppliers

[John_H]

**I would love to try one of the Filtertron kits.

I've built a few of these Terry. They are quite nice.
Amplified parts is one of my favorite suppliers. The customer service is great.

[big_teee]

Mojo has 13% off of everything they sell until the end of October.
Which is a lot of different stuff. Amp parts, pickup parts, tools, etc.
https://www.mojotone.com/

T

[copperheadroads]

Yes the filter-tron kits are quite good .

[jsnace]

Anyone have a recommendation/experience with purchasing sheets of rubberized Ferrite like what might be used in the American 60s gold foils?

[J M Fahey]

Isnīt that basically same material as used in fridge magnets?

[big_teee]

All the craft stores, including walmart, sell sheet refrigerator type magets.
https://www.google.com/search?q=shee...w=1366&bih=576
T

[Helmholtz]

Do fridge magnets have a magnetization pattern and orientation suitable for PUs?

Clamping magnets often have multiple/alternating poles to increase clamping strength.

[jsnace]

I seem to recall reading a post from Lollar that implied they do not.

[SonnyW]

The refrigerator and tool holder type of flexible magnets definitely do have the magnetization in stripes of alternating polarity. I have measured this with my gauss meter, and also viewed it with viewing film. It is called Multipole magnetization. You are probably going to have to get the manufacturer to make it up special order with straight through thickness single magnetization. The '60's pickups that used this kind of magnet had the straight through thickness magnetization, I've rewound plenty of them. The other problem would be in getting some that is thick enough, most of what is available is in pretty thin sheets or strips. I have tried to re-magnetize some of the multipole strips from a magnetic tool holder strip with my commercial MAG-24C magnetizer, and it won't get rid of the multi-pole patterns.

[Helmholtz]

I have tried to re-magnetize some of the multipole strips from a magnetic tool holder strip with my commercial MAG-24C magnetizer, and it won't get rid of the multi-pole patterns.

No surprize, as the flexible magnets are based on ferrite/ceramic magnet particles suspended in a rubber-like carrier material. The high coercivity of ceramic magnets requires much higher demagnetizing/magnetizing fields than alnicos.

[J M Fahey]

The refrigerator and tool holder type of flexible magnets definitely do have the magnetization in stripes of alternating polarity. I have measured this with my gauss meter, and also viewed it with viewing film. It is called Multipole magnetization. You are probably going to have to get the manufacturer to make it up special order with straight through thickness single magnetization. The '60's pickups that used this kind of magnet had the straight through thickness magnetization, I've rewound plenty of them. The other problem would be in getting some that is thick enough, most of what is available is in pretty thin sheets or strips. I have tried to re-magnetize some of the multipole strips from a magnetic tool holder strip with my commercial MAG-24C magnetizer, and it won't get rid of the multi-pole patterns.

Very interesting, thanks.

Just checked your magnetizer specs.
20000 AT per inch is perfect to magnetize *any* ceramic and yours offers 24000 (I guess thatīs where the "24C" label comes from).

So in principle you should be able to browbeat any ceramic, including relatively weak rubber bonded types, into submission.

That said, we have 2 Technical problems which might complicate that:

1) your magnetizer focuses its magnetic flux through a couple heavy iron jaws into a narrow long space, perfect for a guitar pickup, from rods inserted in a bobbin to a rectangular bar.

By the same token a piece of rubberized magnet will get a strongly magnetized area, same shape as magnetizer jaws, hardly a uniform field all over its surface.

Do you have some means of visualizing magnetic fields?
It would be interesting to magnetize a business card size piece of rubber magnet and check whether what I suspect is true or not.

If so, you might try drawing same piece across magnetizer jaws , while pressing the button that is, it "should" magnetize full surface uniformly, this creating a uniform "gold foil" magnet.
Worth trying, donīt you think?

I make my own speakers and currently have 2 brute force magnetizers, the third capacitive discharge one is in the works, can magnetize a 10cm or 15cm disk in a single hit but would love to know if the "sweeping magnet" method works ... since itīs within the possibilities of a relatively inexpensive machine, available to the average pickup maker.

Doubt the popular "passive" magnetizer based on small Neo magnets is strong enough for ceramics.

2) that said, maybe the alternating magnetic pattern is "dyed in the wool"

Meaning the rubber material is vulcanized/cured while under a magnetic field; in which case magnetic ferrite dust orients along flux lines, gets magnetized, and "trapped" in the now solid rubber.

Good to get stronger and well defined magnetic strips, hard to impossible to reorient.

Of course, exprimenting rules and yields the true results.

PS: almost forgot, can you please post the actual jaw dimensions?

That important value is not in the catalog, from pictures I estimate 2.5" or 3" wide by 3/8" high or so but canīt be certain of course.
Thanks.

[SonnyW]

I measured the rubber magnets with the probe of my gauss meter. Just by passing the tip with the hall effect sensor along the magnet and noting the gauss readings and the changes in sign. My meter is an Alpha Labs DC Gaussmeter Model 1. I don't still have the piece of the tool holder magnetic strip that I tried to re-magnetize to straight through thickness pattern, or I would try measuring it again. I am just going on memory. I seem to remember that the field was much weaker, anyway it didn't work.

At one point, I had some magnetic viewing film. I don't have it anymore, or at least I haven't been able to find it in a long time. It's somewhat useful but rather expensive, and in my experience it is really only good for a one time use. At the time I wasn't able to degauss it sufficiently to re-use the sheets. I have a degausser now, I don't know if that would work to make the film re-usable. This was all a long time ago. I think I may have got the viewing film here, if not, it was someplace like this shop:


http://appliedmagnets.com/magnetic-viewing-film-c-7_63.html

Here are a couple of photos. The first one is a picture of one of the jaws of my MAG24C. It is a block of steel 3.25 x 4 x 1 with one face beveled. I have annotated the dimensions on the photo.



The second photo I got from Wikipedia, which shows the multipole pattern of a refrigerator magnet. it must be attributed to its original author:
By Zureks - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=5304630

It was from the Wikipedia article on Refrigerator Magnets. This also mentions an interesting method of magnetizing the rubber magnet called a Halbach Array. Maybe that is what is going on as well. Halbach Array.



Also as a comment, I don't know if my magnetizer will have much effect on the hard ceramic magnets, I haven't tried to use it for that very often, but I seem to remember that it didn't make a lot of difference. The times that I would have tried it is if a ceramic magnet in some pickup I was rewinding appeared to be weak. That hasn't happened that often, and I didn't make any notes, I just seem to remember trying to boost the charge on some of them and it made little or no difference. I hope I have answered all of your questions.

[Helmholtz]

It's somewhat useful but rather expensive, and in my experience it is really only good for a one time use. At the time I wasn't able to degauss it sufficiently to re-use the sheets.

All you need to erase the film is a bar magnet. Just wipe over the film with the long edge of a pole.

I have been using the same viewing films for many years.

BTW, these viewing films get bright if the the magnetic field lines beneath run parallel to film and dark areas show where the field lines are perpendicular to the film plane. I use them to check if magnets are uniformly magnetized. Viewing the flat side, a bar magnet should show a straight bright zone (called the "neutral zone", where north and south poles cancel) running through the middle between the poles. A curved, slanted or off center bright zone indicates a non-uniform magnetization resulting in uneven pole strengths.

[J M Fahey]

Here are a couple of photos. The first one is a picture of one of the jaws of my MAG24C. It is a block of steel 3.25 x 4 x 1 with one face beveled. I have annotated the dimensions on the photo.

[ATTACH=CONFIG]53362[/ATTACH]

Thanks a lot.

Also as a comment, I don't know if my magnetizer will have much effect on the hard ceramic magnets, I haven't tried to use it for that very often, but I seem to remember that it didn't make a lot of difference. The times that I would have tried it is if a ceramic magnet in some pickup I was rewinding appeared to be weak. That hasn't happened that often, and I didn't make any notes, I just seem to remember trying to boost the charge on some of them and it made little or no difference. I hope I have answered all of your questions.

Thanks again.
You didnīt notice much effect (if at all) on ceramics because they donīt lose much (if any at all) anyway.
Now Alnicos weaken every time you move them (relative to the magnetic circuit that is) or let them stick to each other , they are that soft, so they usually benefit from remagging.

[Bodean]

Does anyone have a name of a bulk supplier for 52mm single coil strat pickup covers?
Thanks