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Subject: Re: finding ultra-thin copper sheet?

From: "Bert" <bertd.geo@...>
Date: 2007-03-21

--- In Homebrew_PCBs@yahoogroups.com, "Bert" <bertd.geo@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, David McNab <rebirth@> wrote:
> >
> > Hi,
> >
> > Does anyone know how to get hold of blank PCB material, similar to the
> > usual 1.6mm thick copper-clad stuff, but ultra ultra thin?
> >
>
>
> I've seen copper sheet as thin as 010" and .005" ( .127mm). DigiKey
> sells it. They used to stock it but it looks like special order now
> (just means there will be a delay in receiving it).
>

I found the ultimate thin copper sheet. It's limmited to 1" wide
though. To be able to test the potential of copper sheet, I used 1"
wide copper tape.

I layed out my board to be only 1" wide (no length limit, mine was 3")
and then printed it on a test sheet of paper.
I then placed a sheet of laser transparency over the sheet and placed
a strip of copper tape directly over the image and pressed it down tight.
I then ran the transparency with Cu tape through the printer (oriented
the same way as the test sheet was.
After this, a piece of polyimide tape would be placed over the back
for extra support and Viola ... instant flex circuit.

This was a perfect carrier for printing directly on the copper.
Sadly, as was expected (by ST I think), the copper does not pick up
enough toner. In areas where it did pick it up, the board looks great
but the overall print is spotty. I have a few other things to try but
doesn't look promissing in Lasers.
It make work in an inkjet except I'm not sure how well the carrier
sheet will survive the baking process. If someone tries it, let me know.

I'll post pictures of my results as soon as I take some.
Bert