This video answers the age-new question: Can you solder to silver circuit trace ink?

The answer is yes, but it probably would take some practice, and it doesn’t work all that well.

Update: Overloading a Circuit

Because the impedance of the silver ink was so high, I decided to try and overload it with far too much current to see what would happen.

The video includes trying to power a 40W light bulb at 120 VAC through the paper circuit as well as a dead short at 30 VDC!

The upshot is that it did not start a fire, and the silver trace failed in a controlled manner. That’s bad for the drama of a YouTube video, but a good indication that this product won’t burst into flame in regular use!

Soldering Technique

I got a little more practice soldering onto the ink, and here’s the best technique as I could manage:

1. With the soldering iron at a normal soldering temperature (I used ~380F), tin the leads of the wires or components. Contravening the proper technique, leave a good size blob of solder on there.
2. With the soldering iron at a low temperature (~300F), “tin” the inked paper by flowing solder onto it with the tip just barely not touching the paper. The result should be a small blob of solder on the ink, without having melted the coating on the photo paper.
3. Place the lead on top of the blob that’s on the ink. Heat the soldering iron back up to ~380F or higher, and place it on top of the lead, just long enough to flow the solder on the lead into the solder on the paper.

And that’s it! Using this technique, I was able to make three flawless joints out of my first four attempts. And that was to tack the heavy gauge wire of the 120V power cable to the paper. It was much more solid than I expected.