Black Widow disintegrated vent foam mess FIX

C E Holden · From: Austin, TX

Hi--
Someone may have already posted on this, but I thought I'd throw in my $.02 since I've done this several times now, and I've got a pretty good method for fixing this issue. This is for when the old foam in a Black Widow magnet vent disintegrates and falls into the coil gap. Of course, you probably won't notice for a while, giving the speaker time to nicely work that stuff into the voice coil gap and harden. Then, you'll begin to notice a dragging sound or a rattle from the hardened little bits of foam that are jittering around against the aluminum dust cover.

First, make a small mark with a Sharpie on the magnet and the basket -- when you re-assemble you'll be able to align the marks so it goes back together the same way. While the magnet doesn't care where it sits on the voice coil, you need to have your bolt-holes aligned so you're not having to move anything around too much when reassembling.

**If you are doing this on your workbench, and the last thing you worked on involved filing steel, clean off your bench!**

Next, take out the hex screws and carefully lift the magnet off of the basket.

Now you will see your problem--little bits of black stuff rolling around in the dome and wedged-in gunk that has vibrated its way into the coil gap and is now cemented on to the inside of the voice coil bobbin.

The best thing I have found to take it off is throttle body cleaner which can be bought at your local auto parts store. This stuff is nasty--do not spray it directly on the speaker! Get an old toothbrush and spray the bristles with the cleaner, then apply to the mess. You don't need to put muscle into it--let the solvent to the work. Just gently rub back and forth, and it doesn't take too long for the stuff to come off. Clean your brush periodically with a paper towel and re-apply spray to the bristles. If there's no gunk on the coil side itself, don't mess with it! There shouldn't be--I've done 4 of these now, and the stuff is mostly on the inside of the bobbin. Take a clean, lint-free cloth and gently wipe off the excess solvent and mess.

There will also be stuff down in the magnet as well. Again, spraying only the bristles, angle the toothbrush down into the coil gap and brush, brush, brush. Clean off the excess with the cloth. Also check to see that there aren't any bits left clinging to the wire vent screen, just waiting for the next gig to fall into your newly-cleaned speaker.

There will be bits of hardened junk still in there. Take a piece of masking tape and double it over so you have two sticky sides out. Then run it around the coil gap moving it up and down as you go. You may have to do it a number of times until it's clean. Get a magnifier and look to see that there aren't any bits of junk sticking up in the gap. If you didn't take heed to the steel filings warning above and now have little flecks of steel down in the gap, you'll have to work and work to get them out; the magnet is stronger than your tape.

Now it's all clean and you are ready to re-assemble. Leave the magnet face-up and aligning the marks you made before, lower the basket on to the magnet. If you do it the other way around, you're liable to crush or distort the coil bobbin. With both hands, grasp the basket (where the cloth spider is) and the back of the magnet and carefully flip it over. It's heavy, and it's awkward, so be careful. Put in your hex bolts finger tight making sure they are seated properly, and then go back and cinch them down.

I hope someone finds this information useful.

CE
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"il brutto"

Mark van Allen · From: Watkinsville, Ga. USA

Right on the money, CE. I used to routinely do the tape thing on my BW speakers every 6-8 months just to keep 'em running. Sometimes there'd be quite a bit of gunk in there.
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Stop by the Steel Store at: www.markvanallen.com
www.musicfarmstudio.com

Mike Wheeler · From: Delaware, Ohio, USA

Excellent post C E. An additional tip for cleaning out the magnet gap....

Find a piece of thin, but stiff, plastic (like lighting gel plastic) and cut it about 1/2 inch wide and about 3 inches long. Wrap a 6 inch piece of masking tape around it lengthwise. Then, while holding the tape and plastic firmly together, run the tape around the gap with an up and down motion. Oh, and don't use the cheap tape...it's adhesive can dislodge and get stuck in the gap....not good!

Another alternative is to use a piece of very thin fabric in place of the tape (for tough cases). Soak the tape with the solvent and run that around the gap to dissolve the gunk....but only do it this way if necessary. Lastly use a piece, or two, of dry cloth to finish up.

You'll need to do this several times until, like C E says, you come up with clean masking tape (or cloth).

I've done countless gaps like this back when I reconed speakers. The same procedure applies to all of them and makes the gap cleaning process quick and easy.

Also, when flipping the speaker back over, grip the basket and magnet VERY tightly so they can't slip against each other. You could destroy the voice coil if they did slip. So, be VERY careful.
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Best regards,
Mike

Bill Moore · From: Manchester, Michigan

Good info. Another tip; to keep the magnet aligned when assembling, screw a short threaded rod into each bolt hole. Long enough to go completely through the magnet and extend an inch past it. Then align the holes in the magnet with the threaded rods and lower it. This will give you perfect alignment. Unscrew the rods and install the original screws in their place.

Tom Gorr · From: Three Hills, Alberta

My cleaning method will be: take the speaker out of the amp. Replace with the Eminence Neo magnet or Telonics steel speaker. Everything in this steel business is 40 pounds too heavy!

C E Holden · From: Austin, TX

Stay tuned for the unveiling of my Styrofoam D-10!
_________________
"il brutto"

Freddie Wooton · From: London, ky

Thanks CE I have already done this just once. Didn't know about the cleaner though. Fred

Jim Bob Sedgwick · From: Clinton, Missouri USA

Another tip.... rubbing alcohol will dissolve the black gunk very easily, and it's cheap.

Bill Moran · From: Virginia, USA

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