Soft Circuit Workshop

Technique Report: Conductive Epoxy

Based on my painful experience on sewing 30 LEDs onto a fabric (60 legs, to be exact), thus for my “technique report” i choose to play around with conductive epoxy with the thought i could replace LED connection with a dab of conductive epoxy rather than having to sew on each LED leg.

The product i got is from less emf and it cost $24.95 for a pack. You will get two syringes one is epoxy and one is pure silver. What you need to do is mix 1:1 ratio, stir it well and it’s ready for use.

Logically, it should work, or maybe not. First i found out that it took me around 1/2 hour to get it dry (not 10 minutes like it said on the box) but maybe it’s because the material that i’ve been using. Other than that, here’s what i found:

1. If you apply it really thin, it can work like a conductive paint, in which you can replace conductive thread/fabric, to make a soft switch or battery pouch.

2. When you apply the epoxy onto LED leg, make sure that you sew your circuit line first near where the leg is and put the epoxy ontop/between the leg and the conductive thread. You can also put the epoxy first, but then you have to sew over the epoxy to make the connection (still easier than sewing LED leg).

3. In terms of washing it, i tried two methods: hand wash and machine wash.

First i tried washing it by hand (only dip in water, press toilet tissue to take the moisture out and hair dried on high —> to simulate machine dry) and it’s still intact and remains conductive.

Second, i tried machine wash, two fabric with LED and with no LED (color setting: warm water) and machine dry (permanent press). The result was, when it was out of the wash the “thick” part of the epoxy cracked a little bit, but the “thin” part is okay (can’t check the conductivity because it’s still wet). When it’s out of the dryer the result was the epoxy lost it’s conductivity.

My conclusion will be:

- Conductive epoxy can be used to make connection on fabric, although it has to be used really carefully (and it cost a little bit more compared to conductive thread) and it’s not as durable as the conductive thread or fabric.

- It is HAND washable, maybe not wash, but more of like dip it in a water and hang dry.

- It helps a lot to make quick connections, especially for people like me who have with zero patience / little experience sewin

*I HAVE MORE PICTURES that i have not uploaded because i think i lost my charger,  pictures above were taken using my sister’s camera.