Conductive Paint, Pens and the like

[E:pp:ik]

Hi folks! I'm a x0xb0x section dweller but from time to time I break out of there:) I gotta hang out in these other sections more often. Every time I look in another direction there's great info to be found.

I have a situation where I have some old obsolete push buttons I need to restore. It's one of those arrangements where there's a rubber suction cup with a contact plate inside a sealed casing. When pushed it makes the connection to two metallic pins on a set of plates below. This engages the button.

The contact in this suction cup has worn out. At best the connection is intermittent. I'm trying to find a solution to recover the plate in that suction cup to restore its ability to connect and one possibility was painting or scribbling in some sort of conductive material. I suspect it's not a long term solution though. Can anyone enlighten me on what options exist? I haven't really found anything 'obvious'.

Thanks!

[BruceF]

It isn't something you could build up with a bit of solder?

[E:pp:ik]

I don't think so since it won't adhere to the surface. It's not like a metal contact that could be tinned.

[BruceF]

Could you fit/glue in a piece of copper foil or something? That should be easy enough to find at a craft store.

[E:pp:ik]

I suppose so, but this is going to be used a lot. It's a got to be a rock solid option so I don't have to open it up again for some time. It can't jog loose under any circumstances. I thought that the least intrusive would be some sort of coating (provided it lasts long enough). This is why I was hoping for some sort of commercial grade conductive ink or paint.

[adafruit_support_bill]

The adhesive on copper tape for PC boards is pretty tenacious. You might also look at some of the pressure sensitive elastomers such as Zoflex or QTC.

[E:pp:ik]

Cool. I'll check those out. I started looking at those conductive epoxys but didn't commit. I'll let you know what I settle on and see if it works.

[mikeselectricstuff]

There is a product specifically designed to repair conductive rubber pads on membrane keyboards :
http://www.chemtronics.com/products/pro ... &m=2&id=32

[pstemari]

Haven't tried the Chemtronics stuff for keypad repair, but the conductive pens are unlikely to work. They lay down a fairly hard paint-like coating that would probably chip off a rubber dome.