I know there exists conductive glue but can Adding graphite to different materials makes conductive glue but can graphite be used to make say rubber or a polymer conductive? When the rubber is heated can it be used as solder, can it serve as a conductor? Does anything like this already exist?
Thanks!

 

There certainly are lots of conductive polymers and elastomers ("polymer" is the sort of general category, "elastomer" is a sub-category for materials that are elastic - rubbery) on the commercial market, including things like "RTV" (so-called room temperature vulcanizing) silicone "rubber." There are materials that can be printed with screen ("silkscreen") or stencil methods. Conductive elastomers are used extensively for things like connectors for liquid crystal displays and for keyboard switches. Electrical performance varies considerably depending on the conductive material used in the elastomer matrix. Most are quite high resistance and hence suitable only for low currents.

I don't know of any thermoplastic types that you could use like a low-temperature solder. There are things like conductive polyethylene and thermoplastic polyurethane (not all PU is thermoplastic) that but they tend not to stick well to anything. Even getting such a material to stick to itself is difficult and really requires a welding process where both the filler and the surface of the base material are heated to melting point and fused together. There are conductive pressure sensitive adhesives that can be used to stick things together. You can get "tape" that has conductive spheres in it and use it to stick something like a flexible flat conductor cable to a PCB, but it isn't especially easy to use (needs heat cure with some pressure).

3M makes a number of interesting products. Many are fairly expensive and anything that "cures" to final form usually has a rather short shelf life.

 

There are plenty of products on the market ...

Just one problem ... none of them work(properly) ... look at this one , they've put a line across the soldering iron .... throw it away "no more soldering " ..all lies ...

All these products have some glue base , often epoxy with copper powder/ carbon dust / even silver dust added . And this increases the conductivity , but it's still about 100 times less conductive than solder , so in 99% of applications it's no good.

 

There some high performance electrically conductive adhesives available, but you won't find them at the local hardware store and they are quite expensive. I evaluated some several years ago as an alternative to soldering small very high performance photovoltaic cells (Spectrolab TASC) to PCBs. I don't recall for sure, but I think the minimum quantity I could buy of the type I though best for the job was about US $300. The manufacturer actually made even small quantities to order because of the limited shelf life. Again, this was a curing adhesive, not a thermoplastic material.

 

If you have DirecTV you are using a conductive rubber every time you push a button on the remote. Under the button is a layer of conductive rubber. Probably other remotes use this too but I have only taken a DirecTV one apart/

 

Thanks for the response. Also, other than graphite, what other substitutes are there to make the material conductive?

 

Metallic silver powder is also used in some conductive paints - obviously expensive.

 

You would be essentially be making a resistor with an unknown resistance, something that would not be very efficient or practical in many circumstances.

 

Bareconductive has a conductive paint... Not sure if that would help but it may.