Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Dan Pickard <dlpwebmail@...> wrote:
>
> 
> 
>     I just cropped and removed extraneous images from a file someone had
> uploaded previously of his tests using silk screen emulsion as photo
> etch resist. He just brushed it on. However, as per his later
> messages, which emulsion you use is very important. Not all will stick
> to copper.
> 
>   Thanks, Steve
>   I'm new to the group thing. I found it, Thanks.
>   As for the other posts: the screen printing of PCB works out
perfect for high-run production but it's way to costly for one-off
boards. The ink holds up under etchant for hours. I had a few boards
screen printed for the lab at $100 for two. You have to pay that
set-up fee :-(
> 

Dan, I can't tell what you wrote and what was quoted.

You'd probably not have found those pictures on your own, the
gentleman who uploaded them didn't label them very well.

Yes, screen printing setup charges are spendy. $35 to $75, and in
order to have a screen good enough for a PCB the screen must be a much
finer mesh than those normally used for Tshirts.

The pictures I "fixed", however, are of using the photo emulsion that
normally goes on the screen, right on the board as the etch resist. I
think the idea is that it is supposed to be a lot cheaper than normal
PCB photosensitive etch resist. Not having priced the two, I don't
know. In that particular case, the gentleman involved I think was
unable to find conventional photosensitive PCBs or coating in his country.

Steve Greenfield