Woofer-Based Parts Cleaner Bounces To The Beat

Is there anything more satisfying than building a useful machine from mostly junk? We think not. [ke4mcl] is a big fan of reusing and repurposing things before settling for the recycle bin, and was in the market for a vibratory parts tumbler to quickly clean off old, rusty bits and bobs in the course of repairing old electronics. For just $10, most of which went into a new tube of RTV silicone, [ke4mcl] built their own tumbler and came away with a reusable amplifier setup in the process.

We’ve all seen speaker cones dance, and they are definitely our favorite way to observe non-Newtonian fluids. This old woofer can still move, so it’s got a second life shaking sand and screws around until they’re somewhat shiny. The ideal woofer for this purpose has a rubber surround — that’s the ring that connects the speaker cone to the frame. [ke4mcl]’s foam-surrounded woofer works just as well, though it may not last as long.

After scrounging a container with a screw-top lid that fits the woofer perfectly, [ke4mcl] joined them together with a bead of RTV silicone. Since there weren’t any amplifiers lying around, [ke4mcl] spent a few bucks on a class D amplifier board and found a spare laptop brick to power it. An old phone with a tone generator app gets the sand churning with a friendly sine wave, which you can see in the videos after the break.

We think it’s particularly nice to keep things like fire extinguishers out of the landfill. If you don’t need a parts tumbler, why not use one to make your own refillable, re-pressurizable solvent container?

27 thoughts on “Woofer-Based Parts Cleaner Bounces To The Beat

  1. That’s pretty cool. Does raise some thoughts on high frequency polishing mixed with lower frequency movement finding the optimum frequencies for cleaning based on type of media.

    The amplifier and audio is too easy. Dare I say, this sounds like a job for a 555?

    1. For once, the facetious jab actually has merit! With enough support circuitry, sure. You’d definitely need _some_ sort of amplification stage to actually push enough power to move the voice coil. Also some filtering to move the square wave digital output of the 555 into a vaguely analog waveform… hard square waves at audible frequencies are rough on cones.

    2. Audio Amp: Power supply => pre Amp => output driver stage => speaker

      It would be interesting to work with the dimensions of and enclosure for the speaker and the enclosure for the sand so that it can work at mains frequency 50/60Hz

      Then you bypass a lot of the cost and complexity of the Amp

      Mains voltage => transformer => speaker

      I was considering doing something like this with a cat litter. Applying a mains frequency signal to a speaker under the cat litter so that the cat poo descends into the bottom of the litter box and so it doesn’t need replacing as often.

      1. larger or lighter parts work their way up. Burry a pebble in a bucket of sand and shake. Or crush cookies for the cake, shake and see the larger parts float up. Well, maybe this eases picking the poo from the grid bed. As for the speaker, I’d change it for a bass/body shaker, found in flight simulators: sturdy, cheap, compact.

        1. Was the disk (in the lower left corner of the container) rusted like the nail and nut when you started?

          A local gun shop has a used batch of walnut shell and rouge for sale. I’m tempted to buy it.

  2. Someone at uni had a setup like that. It was a much larger sub with a flat bottomed and straight sided glass dish on it (sharp internal corners). At various frequencies, the granules would form patterns and somehow this managed to result in a thesis.

    Parts cleaner playing deep purple sounds like a much better idea. Though I’d try some Bach too.

  3. Cool and fun, but in practice I doubt I’d want to use something that noisy (as it has to be kept on for a long time to do the trick). If all you want to clean is rust from small iron/steel parts, get some citric acid (vinegar works too, but stinks), dissolve in tap water, plonk in a container over night (or more), done.

    If not rust, I think I’d try to build a rotary tumbler or ultrasonic cleaner, but it depends on the application of course. If you’re in a hurry and the nature of the part allows, it’s hard to beat a bench/die/angle grinder with a wire or flap wheel.

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