Controlled Destruction of loudspeakers Donut Magnet Removal

[Dee Jay]

For my altermotor project, I planned on using a capacitor to excite the electromagnet to gain torque on take-offs. But since I don't do calculations, there's a good chance of burning the coil out so Plan B is to use donut magnets. Plan C would be to upgrade to N42 neomag rotors but it'll be a while till I get to that stage.

I don't know what size donuts I will need for the Delco 10si alternator but I had some big crappy PC speakers I wanted to toss out for spring cleaning and thought maybe they're worth practising on.

I looked around the net and youtube to see how others are extracting the magnets. One vid has a granny hacking away with extreme prejudice... Big ups to Nancy!
[youtube]qDthTKne6mA[/youtube]
And another vid, a guy working on the same size speakers I was about to work on. I was surprized to see him using heat to melt the epoxy.

[youtube]f5o5HEfo8UY[/youtube]

I say, no way, Jose. I didn't want to risk weakening the magnets as I have the tendency to over-do things when working with heat, and once again I'm too lazy as well as impatient to wait for heat to do its thing.. but most of all, this is yet another opportunity for me to improve on magnet extraction techniques that I hope ebikers would find useful.

I also searched for videos on loudspeaker production just to see how they are constructed for more efficent and controlled destruction.
[youtube]P-pzTfc5C08[/youtube]
Anyway, WORDS SUCK so here are some pictures







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45.2mm OD & 21mm ID
58.6mm OD & 31.7mm ID

I imagine it would be far more difficult to deal with bigger speakers with fresh epoxy. Please feel free to add your experiences and pictures to this thread

 

[TylerDurden]

You might try your puller and a heat-gun. Ceramics can take a bit of heat.

 

[Dee Jay]

You might try your puller and a heat-gun. Ceramics can take a bit of heat.

Hi Tyler, good to see you,how you been?

yeah what the guy did on the stove was a bad idea though because he was applying heat directly to the magnets.

View attachment 1

I will also try cold and try to get the tacky epoxy brittle. Anyone know if extreme cold can weaken a magnet?

 

[TylerDurden]

Cold can also make magnets more brittle. Heat will soften epoxy.

Same-ol here... but I don't live south of Fukushima. Glad to hear yer OK.

 

[Dee Jay]

Same-ol here... but I don't live south of Fukushima. Glad to hear yer OK.

Oh yeah man, were fine so far, thanks. Been wanting to get a gieger counter. Among my family and friends, I'm the only one taking things seriously. I think a lot of people here accepted their fate because they have no choice but to stay put. And a lot are playing it cool, but really they're in denial. Then these two groups label people like me as a scare monger and equate "taking action" to "panicking". Then you got those lying tepco idiots wanted to save their precious power plant, unfugginbelievable.. The media wanna paint them as heroes?? :? A heroic thing to do is upgrade their plants..

We may move to the US next year, we'll see