I got the idea for this from Leah Buechley's LED sequins made with crimp beads. I wanted to solder thread connections instead of sewing. I like the flexibility and durability of stainless steel thread but it doesn't solder.* So I developed a "work-around."
I couldn't solder to the thread, but I could solder around it. The trick? String a crimp bead onto the thread, then melt solder into the bead hole. If there's enough solder, the bead stays put. It's easy, and you can add a soldered bead even if you don't have access to the end of the thread (i.e. because the thread is already attached to something).
a needle threader
conductive thread - I'm using Adafruit's 3 ply stainless steel thread.
crimp beads - Choose a size that leaves a bit of a gap between the thread and the bead. For this thread, I'm using #2 beads.
solder (thin enough to fit inside the bead)
stand for holding soldering iron
*For info on other conductive threads, including ones you can solder to, check out Hannah Perner-Wilson's overview or Lynne Bruning's series of thread reviews.
Step 1: To solder the end of the thread
Keep in mind, when you heat the bead up again, the solder inside will melt. If it leaks out, you may need a "refill".
Step 2: To solder in the middle of the thread
If your thread is already stitched into something, you can still solder it, if you've left a little slack.
And that's it. Easy peasy.