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Query: Repairing conductive rubber pads

Posted: 08 Sep 2015, 18:45
by nathanscribe
Does anybody know how best to repair the conductive rubber spots on the underside of rubber domes? This is the 'rubber dome over PCB tracks' type, no membrane involved. I've seen various claims online about sticking foil to them, rubbing pencils on them, using conductive paint, roughening the surface with an eraser... though the conductive paint option sounds promising, I've also seen some bad reviews of the stuff, so I thought there'd be no better place to ask than here.

Caveat: not for a computer keyboard, for a synthesizer keybed, so rubber dome haters need not fear ;)

Also, hello again. It's been a while.

Posted: 08 Sep 2015, 19:41
by Parak
Never done that myself, but if I had to I'd first try something like:

+ whatever size hand punch is needed.

Posted: 08 Sep 2015, 22:27
by Scottex
Parak wrote: Never done that myself, but if I had to I'd first try something like:

+ whatever size hand punch is needed.
this looks like a good idea, conductive paint is messy

Posted: 08 Sep 2015, 22:42
by chzel
I'd be concerned with the tape not adhering well to the dome. It is rubber after all.
Conductive paint would probably work better.
Is the conductive spot worn away so much that it doesn't make contact?
Maybe transplanting a thin sliver of the conductive material from a cheap remote control or something?

Posted: 09 Sep 2015, 17:21
by nathanscribe
Is that tape actually conductive, though, or metallic with a non-conductive coating?

I've read comments on how the paint wears off relatively quickly, so the jury's out on that at the moment.

As for the rubber itself, pressing down really hard on the key activates the switch, so I'm guessing that what's happening is the extra pressure is deforming the conductive spot to the point where its un-worn edges are making the contact instead of the probably-worn-out lower surface.

At this moment, I'm even considering double-sided tape and some kitchen foil...

Posted: 10 Sep 2015, 00:07
by Parak
Metalized mylar is supposed to be conductive. If it isn't and you have amazon prime, you could just return it.