Can I use solder paste to create traces?

[JeffB]

I know that the original plan in the kickstarter campaign was to have solder paste and non-conducting paint, and how that didn't work out, but why conductive ink and solder paste? Why not print everything using solder paste?

Thanks,

Jeff

[emcniece]

My guess is board adherence - I can't imagine that solder paste alone would stick well to fiberglass.

[mewertow]

Hi Jeff,

What Eric said is correct - the main issue is that solder paste will only stick to a metal that it can alloy with. If you tried to reflow the solder paste on a bare substrate, it would just ball up.

As it turns out, making sure that the ink will print nicely is a large part of what makes conductive ink formulation challenging. The ink needs to have a high metal content to get good conductivity, but also must include components like rheological additives to make sure you can print properly, and binders to help it stick to the surface of the board. It's a careful balancing act that needs just the right mix of everything to work out!

Cheers,

Matt Ewertowski

[Eriond]

I noticed the included boards are covered with a green solder mask. Is this a neccesary feature, or could we use "bare" (single-sided) boards that many of us have laying around from our pre-Voltera period ?

[jazozaya]

Hi Eriond,

It is entirely possible to use bare FR4. The ink will adhere to it no problem.

We found the green solder mask offered a good contrast with the ink and allowed us to better assess the print quality (compared to that yellowish color raw FR4 has).

Regards,
Jesus Zozaya