Homebrew PCBs

David, thanks for the great description of your process. I have one question
however:

On 2/20/06, David Hopkins <davhop@...> wrote:
[snip]

>
>
> To hold the board and artwork together I use two sheets of 10mm glass 300
> x
> 300mm. The sensitized board and the artwork are held between the two
> sheets
> of glass and they are held together with large spring paper clips. The
> reason for two sheets of glass is to do double sided boards.
>
> Before the glass I used to use 10mm Perspex (Acrylic) however this
> scratches easily and one of the trainees spilt developer on them and
> ruined
> the Perspex.


Doesn't glass (or at least most kinds of glass) tend to absorb UV rays? I
was under the impression that this was the case. As a result I first tried
using acrylic, and after finding that it scratches too easily, ended up
using the thinnest glass I could find -
http://www.krupin.net/serendipity/uploads/pcb_making_exposure_frame.jpg

It sounds to me that using thick glass would seriously slow down the
exposure time, especially for people who are using a less powerful light
than the one you have.

Vlad
--
Vlad's shop
http://www.krupin.net/serendipity/index.php?/categories/2-metalworking


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