An interesting thing happened while gluing a voice coil..

On over-excursion of a woofer(s) run in Dipole, there was a loud "POP"..

Turns-out it was the cone hitting the VC leads which were sloppy-large: plenty of VC lead, but the natural bend down to the VC sagged to low: on recovery the cone slams into that "sag" from the VC lead.

Fortunately there is enough lead there to sort of "lift and separate" (like a bra on an old woman :yuck: ) and still allow for more than enough excursion (even when pushing well beyond the gap).

My solution then was to put some felt tabs on the frame (inside/underside) near the driver's terminals and "lift/separate" them to those felt tabs. This puts the lead's just coming off of the driver's terminal stuck to those tabs.



..so, I pull-out the "crazy" glue (Cyanoacrylate), use gloves (disposable), glue the leads and press them firmly on the felt tabs for almost a minute.

-and the interesting thing was: it didn't hold.. at all. (..stuck wonderfully to the gloves though).

I don't think I've ever had that type of glue NOT work before, but something about the VC (flux?) - just wouldn't work with that type of glue.

The fix was easy of course: hot glue gun. :D

-burnt my finger a little though (..4 times - it was 2 drivers). :eek:
 
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Guess felt tabs being way too porous absorbed very liquid cyanoacrilate away from the point where it was actually needed.

I manufacture speakers for a living and use Industrial Epoxy there.

Way thicker than cyano which is actually useless, I mean the common general purpose on.

There is a range of speaker specific cyano adhesives, which comes in a gel form; including one which is loaded with micro rubber balls, think finely ground car pneumatics.
It´s even black, go figure!!!!

Voice Coil Bonder 360 - Hernon

Voice-Coil-Bonder-360.jpg
 
-not the Felt (..it's actually quite dense and about only 1/16" thick for the felt itself). Glove stuck to that! (..also the glove would have stuck to the VC lead, and it didn't).

Yeah, something a bit more commercial and viscous might well have worked. Cool stuff.

I just hadn't come across anything that the cheap stuff wouldn't work on (..though I'm assuming uhmw plastic wouldn't work either).
 
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There are only very few cases for which the ordinary Cyanoacrylate glue really works. One of them is between thumb and index finger. Veeeeery flat and smoth surfaces (like glass for instance) work very well too.

For all the other cases the gel type Cyanoacrylate glue works best. And it offers the user a few minutes for adjustments etc.

Regards

Charles