Homebrew PCBs

----- Original Message ----- 
From: "patroclus04" <patroclus04@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, April 08, 2006 10:45 PM
Subject: [Homebrew_PCBs] My first PCB (photo-resist).


>I just made my first PCB. I did two of them, with different expossure
> times.
>
> Two 6W blacklight tubes, 7 cm away from the PCB, trough a 0.5mm glass.
>
> First, I did 5 minutes exposure. Then, 2 minutes 30 seconds in
> metasilicate developer. It came out quite well. All shiny. But it
> seems that when I took it out of the developer, and tried to clean
> with a soft dumped paper, some of the etch-resistant tended to difuse.
> So I stoped, then washed it with lots of fresh water, and then dry it
> with some toilet paper.
>
> It came out well, but some borders not perfectly defined. So, I tried
> more expossure.
> This time 7 minutes, 30 seconds, and 2 minutes in metasilicate.
> This one came out better defined, but tracks were thiner, and a little
> section of a thin track dissapear.
>
> These are my conclusions...
> the second board was overexpossed. I should try near 5 minutes, and
> near 2 minutes in metasilicate.
>
> But I find hard to know when developing is over, because I see a light
> gray layer over the bare copper areas, and I don't know if it is
> finished or not. And  don't know if I can safely clean it with a soft
> paper, or this way I can take it off!
>
> Any help about this to get better next time??

Your artwork might not be dense enough. How are you making your 
transparencies?

Leon 

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