Copper foil construction

Some time back I read about an Amateur who had discovered a copper foil with an adhesive backing. He was experimenting with using it for PCB
construction. At the time I thought;- “I must try that”. It took quite some time but I finally found some to play with.

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Now I wish I could properly credit where the original idea came from (It was not mine) but it was so long ago I’ve forgotten which Journal I was reading. Perhaps GQRP Sprat or maybe even VK-QRP Lo-Key.

Anyway, I finally found some copper foil. The like of which I think was being referred to in the original article. I found it on eBay (where else) and ordered a small roll. I gather it’s intended purpose is for creating RF shielding for enclosures.

The blurred image above (Sorry, I’ll take some better photo’s later) shows the result. A paper hole punch for creating confetti dots was used to punch out some pads. Three dots were then stuck to a white sticky label on top of the PCB. Then a transistor was soldered to the dots.

So “Yes”, it works.

Is it quick and easy? So much so that I won’t be picking up my Dremel again? No, not yet. At least not without some refinement. The cheap hole punch causes the foil to buckle. A more expensive two-hole punch works fine but you can’t easily see to properly align the holes your punching. So you end up with a lot of wastage. Of course it is dead easy to cut odd-shaped rectangles with a pair of scissors.

Even the act of removing the backing tape from the “dot” and sticking it down is fiddly and somewhat time consuming.

I also worry about the stray capacitance between the copper foil sticker and the copper sheet of the PCB proper. The two being separated only by the width of a paper sicker. Stray capacitance could get quite high here.

But with some refinement the technique shows obvious promise. So while the Dremel may not be due for retirement any time soon I can see a “hybrid’ construction technique developing.

Utopia would be a box of 500 easily dispensed white paper dots, each containing three little copper dots.

Anyway, I’ll keep playing with the idea.

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