Neodymium-iron-boron polymer magnets

[MrCandy]

Bonded magnets - are polymer permanent magnets. They are made from a mixture of magnetic particles, magnetically properties of the polymer binder and various additives. Depending on the physical properties of the polymer binder Bonded magnets can be tough, plastic (thermoplastic) and elastic (magnitoelasty). The advantages of bonded magnets in front of sintered magnets are more high-technology manufacturing, corrosion resistance and, consequently, long life, the ability to manufacture products of complex shape with high accuracy (dimensions with tolerances of 3 - 4 class) and with a complex configuration of the magnetic poles (in the including multi-pole).
The benefits of using magnets also include:

1) Significant reduction in weight of the magnets (2 times);
2) Possibility of a smooth change in the physical parameters of products within the boundaries due to the properties of the materials used;
3) Preferred in comparison with sintered magnets mechanical and strength characteristics (not brittle, which significantly reduces marriage to production);
4) virtually non-waste and cleaner production;
complete interchangeability with sintered magnets, ie, no need to adjust the process in industrial production;


For the manufacture of magnetic powder we use alloys neodymium-iron-boron, samarium cobalt as well as other materials. As a binder polymer can be applied epoxy, phenolic and polyester resins, thermoplastics (based on polyamide, polyvinyl chloride, polystyrene), elastomers (vinyl, nitrile rubber, rubber). The content of magnetic powder in the mixture can reach 76% by volume or 94% by weight. The composition of the magnetic powder and its content in the mixture depends on the magnetic properties of the resulting magnets.

The thing is that:
In bass guitar you can use NEO magnets, but in electro guitar you can use only small size NEO magnets, because the big one will pull the strings.
Bonded magnets can be excellent alternative in pickup construction where AlNiCo will lose charge and where you are not satisfied with the sound of ceramic magnets.
This magnets can be charged in A2-NEO N32 range. And they will not lose their charge. They can work in an environment where the temperature is 200 Celsius degrees.
Easily handled.

The main idea is that we can produce these magnets if certain number of people will be interested.
So please leave your coments.

[Mike Sulzer]

Not sure what you are saying. Do you mean that bonded magnets made with neo material could also have other materials so that in addition to duplicating the field strength of a particular type of alnico, for example, they also could duplicate its conductivity and permeability? Or would such magnets be like ceramics, low in permeability and very low in conductivity?

[MrCandy]

Not sure what you are saying. Do you mean that bonded magnets made with neo material could also have other materials so that in addition to duplicating the field strength of a particular type of alnico, for example, they also could duplicate its conductivity and permeability? Or would such magnets be like ceramics, low in permeability and very low in conductivity?

There is pickup constructions(for example rails single coil size) where you can not put alnico magnets, because tese magnets will lose its charge, and ceramic magnets can have not suitable sound.
Of course these magnets by its permeability and conductivity wont be like AlNiCo and will be closer to Ceramic. But tone will be different.
But bonded magnets have an advantage. You can make complex shapes of the magnet for integration into complex pickup constructions and it will not affect the magnet price.
Also we can produce these magnets with desired field strength.

In near future we will make sound tests on this issue.

[David Schwab]

I've used small neo magnets in dual rail Strat pickups, and they work well there. It's easy to find small size neos for that.

But I can see where a shaped magnet could be very interesting.

[FunkyKikuchiyo]

It sounds like a great idea. I've done a lot of work with neos and there is a lot of potential there.

I've had a thought in the back of my head for strat pickups where no parts are conductive (except the wire, of course), and it seems like a rod material of what you're suggesting would be perfect. I haven't been able to try my idea since I don't want to do it with a ceramic rod (is there such a thing?) and a neo rod is conductive AND too strong anyway. I'm not sure that I'd use a bar magnet in this style, since I can simply use smaller neos in lieu. Then again, I'm not a big PAF guy, so maybe a bar magnet like that would work brilliantly.

I'm not sure how you'd do the binder, but if it was me I'd go with the ones with high dielectric strength (pretty much the thermoplastics you listed are the ones that come to mind for me) and ones that have pretty good temperature resistance, so that normal potting methods wouldn't cause problems. Of course I realize that the more you go by those two criteria the more expensive/difficult it would be - polycarbonate or PTFE I'm sure would be a royal pain in the fanny, if not impossible. You didn't mention PP or HDPE in your list... would those work?

[Mike Sulzer]

There is pickup constructions(for example rails single coil size) where you can not put alnico magnets, because tese magnets will lose its charge, and ceramic magnets can have not suitable sound.
Of course these magnets by its permeability and conductivity wont be like AlNiCo and will be closer to Ceramic. But tone will be different.

You sure about that? Magnets have field strength, permeability, and conductivity. Why would a magnet such as you describe with low permeability and conductivity be any different from a ceramic with the same field strength, size, and shape?

And why not just use small neos and other core material to establish the overall permeability and conductivity that you want?

[Mike Sulzer]

It sounds like a great idea. I've done a lot of work with neos and there is a lot of potential there.

I haven't been able to try my idea since I don't want to do it with a ceramic rod (is there such a thing?) and a neo rod is conductive AND too strong anyway.

There are ceramic rods; I have used them in various pickups, including those with six coils. Why would you not want to use them if you are interested in a pickup with a high Q resonance? If you want lower Q you can use steel, with its eddy currents, or load with a resistor if that gives the sound you want.

[salvarsan]

Searching on "flexible rare earth magnets", I find specs like B field ~5500, coercivity ~4500 Oersteds, and energy product 6-9 mgOe.
Field strength: weaker than most AlNiCo's
Coercivity: between ceramic 8 and rare earth.

Understanding that, I'm sure someone can build pickups with it. Tom Anderson has done so in the past.

[frankfalbo]

...I'm sure someone can build pickups with it. Tom Anderson has done so in the past.

Yes this thread is receiving a phone call...wait...okay the caller ID says "Tom Anderson from 25 years ago" LOL

Kidding aside what has always intrigued me was the ability to make shapes and control things like return paths and subsequently field strength at distant increments, (both within and beyond coil geometry) and to do so without being boxed into simple geometric shapes augmented by steel appendiges. I've even dreamed of a type of "magnetic paint" that would be aligned by a magnet within proximity while the "paint" was curing. Not like ferrofluids, which don't retain magnetism, but more like what Mr. Candy is referring to but with highly customized polar patterns, built in focusing and defraction, etc. If Mr Candy can make truly custom pieces, that could be motivating for someone like us, but doesn't assist in a group buy due to the specialized nature of the part, and any company our size or a guitar company would request the exclusive on the part as well.

[Mike Sulzer]

Yes this thread is receiving a phone call...wait...okay the caller ID says "Tom Anderson from 25 years ago" LOL

Kidding aside what has always intrigued me was the ability to make shapes and control things like return paths and subsequently field strength at distant increments, (both within and beyond coil geometry) and to do so without being boxed into simple geometric shapes augmented by steel appendiges. I've even dreamed of a type of "magnetic paint" that would be aligned by a magnet within proximity while the "paint" was curing. Not like ferrofluids, which don't retain magnetism, but more like what Mr. Candy is referring to but with highly customized polar patterns, built in focusing and defraction, etc. If Mr Candy can make truly custom pieces, that could be motivating for someone like us, but doesn't assist in a group buy due to the specialized nature of the part, and any company our size or a guitar company would request the exclusive on the part as well.

The only place where the value of the permanent field matters is where the string is, and there are many ways to achieve a particular value of the field there. (For example, see the analysis in the current thread "Light Reading" for an analysis based on just that fact.) I do not think that those things that you mention are useful.

[FunkyKikuchiyo]

There are ceramic rods; I have used them in various pickups, including those with six coils. Why would you not want to use them if you are interested in a pickup with a high Q resonance? If you want lower Q you can use steel, with its eddy currents, or load with a resistor if that gives the sound you want.

I wasn't aware of the ceramic rods out there. I'd like to try that, too. I wouldn't try it so much expecting an amazing pickup, but more because I'd want to know personally what the effect is on sound. There is a lot of talk that two grades of alnico charged to the same magnetic strength will have different sounds in a guitar pickup application, and it seems like an interesting experiment - if the rod material itself can have an impact on sound regardless of field strength, then it would prove it or disprove it, I think... or at least make for some interesting data.

[CRU JONES]

You sure about that? Magnets have field strength, permeability, and conductivity. Why would a magnet such as you describe with low permeability and conductivity be any different from a ceramic with the same field strength, size, and shape?

And why not just use small neos and other core material to establish the overall permeability and conductivity that you want?

I think this is a good point.

Is it possible to change the formulation to control Permeability and Conductivity?

If we could, a design could be "community owned" and be funded by individuals "going in". I would most likely be "in", but; Mike hits it on the head in the above quote. I'm trying to imagine an "awesome" magnetic shape, but if it has really low permeability and conductivity... Basically what Mike says :-)

Any ideas on "awesome shapes".

Ethan

[David King]

The LAce Sensor pickups use(d) flexible ferrite magnetic sheet material and they sound nothing like ceramic pickups so I'd be of the opinion that a soft elastomer matrix around a hard magnetic material (high coercivity) will give very different results from it's sintered or molten-cast cousins.
One could do the same thing with alnico filings, just charge them first and cast them inside a magnetic field to get the correct alignment while the elastomer sets up in the mold. I probably have enough alnico filings around my grinder to oblige.

I see DIY benefits, no need for fancy grinding equipment to make custom sizes and shapes with just the right mixture to get the sound you want starting with inexpensive inputs (after a lot of messing around). Easily scalable too.

[frankfalbo]

The only place where the value of the permanent field matters is where the string is, and there are many ways to achieve a particular value of the field there. (For example, see the analysis in the current thread "Light Reading" for an analysis based on just that fact.) I do not think that those things that you mention are useful.

I absolutely love that you don't think any of it useful. I'm not looking for a debate, just clarify for us you really believe so long as gauss strength is set proper around the string, the return path and gauss strength at other locations within the coil are of no value? The only place of value is where the string is?

[frankfalbo]

One could do the same thing with alnico filings, just charge them first and cast them inside a magnetic field to get the correct alignment while the elastomer sets up in the mold.

I don't think the Alnico will hold the charge permanently.