DIY Pyralux for Flexible Circuits

Intro: DIY Pyralux for Flexible Circuits

Flexible circuits have their uses in many applications but the fastest growing application is in wearable electronics. I was originally interested in making a flexible circuit to be fixed to the circumference of an acrylic disc, so after browsing instructables I came across a very good instuctable that used a substance called "Pyralux". The instructable can be found here: https://www.instructables.com/id/DIY-Flexible-Print...

However, I soon discovered that living in the UK meant that getting hold of Pyralux was very expensive! but after realising the Pyralux is simple copper coated Kapton Tape, I decided to try an make my own Pyralux.

The DIY Pyralux is made from Kapton tape, which is a polyimide plastic capable of withstanding high temperatures, and copper tape, often sold as "Slug repelling tape". Both these items had a combined price well under the cost of shipping a piece of real Pyralux to the UK.

The process is super simple and I was able to make a working LED bracelet in just a few minutes.

STEP 1: DIY Pyralux

I first stuck the Kapton Tape to a piece of acrylic for easy removal after. I ended up layering 3 pieces of Kapton on top of each other to give the circuit some rigidity and thickness. Kapton tape is actually very thin. I found it easier to use a cardboard tube to roll the tape on. Air bubbles can be annoying but didn't seem to hinder function too much, but still best to try and avoid them.

I next peeled and added a single layer of the copper tape and that's all there is to it.

To make a simple circuit, I used a craft knife to cut a design and then peeled away the unnecessary copper. I was also able to flatten the DIY Pyralux enough to machine a design and make a working circuit using LEDs and a coin battery. Soldering onto the copper was simple and didn't give me any problems. The final test would be to chemically develop a circuit with etchant solution. I'm not sure if the tape adhesive would withstand chemical development but I didn't have any etchant to test this.

And that's about all there is to it! If any one wants to test this with a chemical etchant than I'd be eager to hear how it turned out. :D

Comments

[GaryC6]

You can apply a resist to the copper Sharpie pens work as resist. A new pen is best. If you can get the industrial sharpie even better. Draw the copper you want left and etch with printed circuit board etchant. You can order this from electronic supply houses. Ferric chloride is one of the etchants used. No cutting necessary. There will be gum left you may know how to deal with that. But the gum will still be there after the copper is gone.

[mcgivervii]

If you want to etch a circuit you might first apply the copper tape to a glass substrate and use a laser printer to print the circuit on glossy photo paper then apply the laser mask to the copper using an electric iron, then etch the copper on the glass and then use a razor to remove the circuit from the glass and apply it to the sticky side of the Kapton tape, solder your components and seal with another piece of Kapton tape. In Theory this should work.. good luck.

BTW.. use Pyrex glass to withstand the heat of the Iron, maybe a large Pyrex cake/casserole dish/pan.

[tdonoclift]

That is indeed a good idea, but I'd have to be super careful when removing the circuit from the glass and transferring it to the Kapton; it would rip very easily. Perhaps after the copper was etched I could soak it in acetone to dissolve the glue somewhat and peel it directly off the glass with Kapton tape. Worth a try I think, thanks for the advice :D