Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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jtaylor
 
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Default conductive rubber glue?

The more I think about this the longer a shot it appears likely to be, but
here goes anyway:

I have a car radio with button switches that don't work. Buttons for bands,
memories, that sort of thing.

The switches are a plastic button, a printed circuit with two traces, and a
kind of black rubber doughnut with a tit in the middle. The tit sticks out
a bit more from the bottom of the assemble, so it hits one pc board trace,
the joint between the tit and the ring flexes, then the ring hits the other
pc trace, and the switch is closed.

Many of these little rubber things have broken where the tit is joined to
the dougnut. I'm off to another car radio repair place tomorrow - at the
really good electronics place that I go to first the guy just shook his
head, so I don't have much hope of finding new bits. This radio is old and
foreign.

Is there a conductive flexible rubber glue?


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Active8
 
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On Mon, 20 Dec 2004 22:01:41 -0400, jtaylor wrote:

Is there a conductive flexible rubber glue?


I got some Nickel Coat (Kote?) from Bainsville Electronics,
Baltimore. Get that or whatever they have.

--
Best Regards,
Mike
  #3   Report Post  
Jerry G.
 
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There is something called a remote control kit for fixing the buttons. This
is an adhesive conductive coating that is painted on to the buttons to make
them conductive again. It is formulated to stick to the type of silicon
rubber that the pad buttons are made out of. Regular contact cement, and the
others will not stick to the pad buttons.

Many of the electronic parts suppliers can supply this kit for servicing the
pad buttons.

--

Jerry G.
=====

"jtaylor" wrote in message
...
The more I think about this the longer a shot it appears likely to be, but
here goes anyway:

I have a car radio with button switches that don't work. Buttons for bands,
memories, that sort of thing.

The switches are a plastic button, a printed circuit with two traces, and a
kind of black rubber doughnut with a tit in the middle. The tit sticks out
a bit more from the bottom of the assemble, so it hits one pc board trace,
the joint between the tit and the ring flexes, then the ring hits the other
pc trace, and the switch is closed.

Many of these little rubber things have broken where the tit is joined to
the dougnut. I'm off to another car radio repair place tomorrow - at the
really good electronics place that I go to first the guy just shook his
head, so I don't have much hope of finding new bits. This radio is old and
foreign.

Is there a conductive flexible rubber glue?



  #4   Report Post  
Steve Dunbar
 
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jtaylor wrote:

....
I have a car radio with button switches that don't work.

....
Is there a conductive flexible rubber glue?



See http://www.sandman.com/rubberb.html.


--
-- Steve
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Richard H.
 
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jtaylor wrote:
Is there a conductive flexible rubber glue?


Another option: Aluminum tape. Used for furnace ductwork; purchased at
the hardware store in a roll like duct tape. It's thin metal foil with
strong adhesive on the back. A great fix for membrane keys that've lost
their conductivity.

Richard


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Randal O'Brian
 
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I have used this on a membrane key pad. Don't put on a thick coating, or it
will flake off.

http://shopping.netledger.com/s.nl/c...lQzNp65In0_ _

There is also a two part conductive epoxy, but I don't remember
the brand name.

Randy


"Richard H." wrote in message
...
jtaylor wrote:
Is there a conductive flexible rubber glue?


Another option: Aluminum tape. Used for furnace ductwork; purchased at
the hardware store in a roll like duct tape. It's thin metal foil with
strong adhesive on the back. A great fix for membrane keys that've lost
their conductivity.

Richard



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Guy Macon
 
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Richard H. wrote:

Another option: Aluminum tape. Used for furnace ductwork; purchased at
the hardware store in a roll like duct tape. It's thin metal foil with
strong adhesive on the back. A great fix for membrane keys that've lost
their conductivity.


Aluminum is a poor choice. When exposed to air it forms a
non-conductive layer of aluminum oxide. Tin or Gold-plated
or even Copper foil would work far better.



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James Sweet
 
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"Guy Macon" wrote in message
...

Richard H. wrote:

Another option: Aluminum tape. Used for furnace ductwork; purchased at
the hardware store in a roll like duct tape. It's thin metal foil with
strong adhesive on the back. A great fix for membrane keys that've lost
their conductivity.


Aluminum is a poor choice. When exposed to air it forms a
non-conductive layer of aluminum oxide. Tin or Gold-plated
or even Copper foil would work far better.




That tape seems to remain pretty shiny over time, it may not be pure
aluminum.


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NSM
 
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"James Sweet" wrote in message
news:as_xd.3081$2X6.1210@trnddc07...
|
| "Guy Macon" wrote in message
| ...
|
| Richard H. wrote:
|
| Another option: Aluminum tape. Used for furnace ductwork; purchased at
| the hardware store in a roll like duct tape. It's thin metal foil with
| strong adhesive on the back. A great fix for membrane keys that've
lost
| their conductivity.
|
| Aluminum is a poor choice. When exposed to air it forms a
| non-conductive layer of aluminum oxide. Tin or Gold-plated
| or even Copper foil would work far better.
|
| That tape seems to remain pretty shiny over time, it may not be pure
| aluminium.

I believe it has a coating of lacquer over a VERY thin film of aluminium, so
that's another reason to avoid it.

N


  #10   Report Post  
NSM
 
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"Si Ballenger" wrote in message
...
| On Tue, 21 Dec 2004 18:01:20 +0000, Guy Macon
| wrote:
|
|
| Richard H. wrote:
|
| Another option: Aluminum tape. Used for furnace ductwork; purchased at
| the hardware store in a roll like duct tape. It's thin metal foil with
| strong adhesive on the back. A great fix for membrane keys that've lost
| their conductivity.
|
| Aluminum is a poor choice. When exposed to air it forms a
| non-conductive layer of aluminum oxide. Tin or Gold-plated
| or even Copper foil would work far better.
|
| Sounds good. So where can these adhesive backed foils be easily
| purchased at a reasonable price?

Copper foil is used for crafts but may be too thick.

N




  #11   Report Post  
John Woodgate
 
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I read in sci.electronics.design that James Sweet
wrote (in as_xd.3081$2X6.1210@trnddc07) about
'conductive rubber glue?', on Tue, 21 Dec 2004:
That tape seems to remain pretty shiny over time, it may not be pure
aluminum.


What happens is that an oxide film forms almost instantaneously, but it
is exceedingly thin and has a very low breakdown voltage. So unless you
want a good contact for millivolt-level signals, aluminium will work
reasonably well. But gold is better, and consequently costs more.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
  #12   Report Post  
James Sweet
 
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"NSM" wrote in message news:xr%xd.10649$KO5.8081@clgrps13...

"Si Ballenger" wrote in message
...
| On Tue, 21 Dec 2004 18:01:20 +0000, Guy Macon
| wrote:
|
|
| Richard H. wrote:
|
| Another option: Aluminum tape. Used for furnace ductwork; purchased

at
| the hardware store in a roll like duct tape. It's thin metal foil

with
| strong adhesive on the back. A great fix for membrane keys that've

lost
| their conductivity.
|
| Aluminum is a poor choice. When exposed to air it forms a
| non-conductive layer of aluminum oxide. Tin or Gold-plated
| or even Copper foil would work far better.
|
| Sounds good. So where can these adhesive backed foils be easily
| purchased at a reasonable price?

Copper foil is used for crafts but may be too thick.

N



And shielding, sticky copper tape is readily available.

I find though that those keypads don't really lose conductivity, they simply
become saturated with skin oils. A good scrub of the membrane and circuit
board with liquid dish detergent has fixed every one I've encountered yet.


  #13   Report Post  
Richard H.
 
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Guy Macon wrote:
Aluminum is a poor choice. When exposed to air it
forms a non-conductive layer of aluminum oxide.
Tin or Gold-plated or even Copper foil would work
far better.


Very possible it is tin, considering it's been aging in my shop for
about 10 years before I put it to use... and still shiny.
  #14   Report Post  
NSM
 
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"Richard H." wrote in message
...
| Guy Macon wrote:
| Aluminum is a poor choice. When exposed to air it
| forms a non-conductive layer of aluminum oxide.
| Tin or Gold-plated or even Copper foil would work
| far better.
|
| Very possible it is tin, considering it's been aging in my shop for
| about 10 years before I put it to use... and still shiny.

It may be vacuum deposited aluminium with lacquer over it.

N


  #15   Report Post  
DoN. Nichols
 
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In article ,
Si Ballenger wrote:
On Tue, 21 Dec 2004 18:01:20 +0000, Guy Macon
wrote:


[ ... ]

Aluminum is a poor choice. When exposed to air it forms a
non-conductive layer of aluminum oxide. Tin or Gold-plated
or even Copper foil would work far better.


Sounds good. So where can these adhesive backed foils be easily
purchased at a reasonable price?


Hmm ... check your local electronics hobby store for the kind of
tape used to build up "printed circuit" boards, instead of the more
common etching away of the unwanted copper from a fully copper clad
board.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
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