Liquid graphite

[cimo]

anybody s got a good idea how to deal with this stuff for rubber button pads?

http://www.coates.com/electro/circuits/news/connections/pcb.htm

[Sasha]

You should get some usage instructions with it. For rubber pads I would clean the surface with alcohol and use small painting brush to apply it. I dont believe there is some special process.

I hope it is not for sparkfun buttons. If it is, please tell us so we don`t buy it.

EDIT

I just find  the line:

PRINTING AND DRYING

Coates Conductive Inks XZ302-1 HV and MV are suitable for use on hand, semi-automatic or fully automatic screen printing machines

Good luck

[Screaming_Rabbit]

anybody s got a good idea how to deal with this stuff for rubber button pads?

http://www.coates.com/electro/circuits/news/connections/pcb.htm

Industrially it's done by screen printing (like I told you once in the chat).

You could use a self adhesive foil, cut the areas out where you'd like to print the pads onto the board (e.g. with a cutting plotter, most public relation companies have them).

Like I told you, the challenge will be to get a nicely plain surface, which is not convex. - But I see a chance, if you use this technique, you'll be able to spread the garphite-paint over the sunken (cut out) pads with a spattle and achieve this way, that the pads have the same hight as the stencil foil. Then, when it's all dry and before you remove the stencil foil, you can sand the pads with a very fine sanding paper.

Greets, Roger

[cimo]

..as i told you i think you are a smart guy  ;)

.. lemme ask a old friend of mine if i can get a SFs pad print laser cut on some plastic sheet..

simone

[Sasha]

You cannot laser cut Silicone, but you can screen or tampon print it.

[cimo]

geee stamp is the right word! and they do it in every city!! i think that with a bit of patience and drill press you can do it in different layers over and over to get it thicker!

let s take the SF buttons for example: i would etch the pads prints just as two concentric circle without the tiny lines inside, and then apply the stamp with the liquid graphite

here s another option (thanks Karlos!)

http://www.instructables.com/id/SEOH3GFFABRWUOD/

EDIT: rubber stamp works cause they re used on paper which will suck the ink, hence the more the pressure the more ink you get in the paper.In this case make some kind of thin shim would be required to prevent the stamp to be squished against the pcb (which won t suck any ink) letting the ink go all over the place.

[karlos]

Here is another link of a carbonk ink, this one from a spanish distributor:

http://www.cemesa.com/busqueda.asp?odes=up&idarticulo=7926&modo=ver&idproveedor=59

lokking forward for photos of the experiment :)!

Regards,

Carlos