Homebrew PCBs

I found that an old overhead projector worked. It needs to have a mercury
lamp (they are the more 'modern' version, with whiter light, mine is 3M
brand). About 1 minute exposed my boards pretty well.

I used it because it has a convenient flat glass surface, and the light
seems to be evenly distributed, and it exposes quickly. I'm not totally sure
about the 'collimation' or angle of the light, but it seemed to work fine
for my purposes and i used it for a 0.5mm pitch chip.

If I was going to build an exposure box, I would consider re-purposing on
old overhead projector, or even a broken digital projector - I think those
have mercury lamps.

On Tue, Jan 26, 2010 at 11:35 AM, David Griffith <dgriffi@...>wrote:

>
>
>
> I'm convinced now that I should give the photographic method a try and
> even try pre-sensitized boards. I'd like to do things the Right Way
> instead of going sloppo like I have been so far. That might explain my
> previous problems. Anyhow, I'll start with constructing a UV exposure
> box. The box and timer stuff seems straightforward enough, but what I'd
> really like is to make a gizmo that sandwiches the PCB and films between
> two sheets of glass or lexan. The idea is to put the things in this
> frame, adjust for registration, clamp it closed, and that's it. Insert
> into the UV box for exposure. I saw a page a couple years ago discussing
> something like this, but I can't find it anymore. Does anyone here smell
> what I'm cooking?
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>
> --
> David Griffith
> dgriffi@... <dgriffi%40cs.csubak.edu>
>
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>  
>


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