Dick wrote:

Has anyone home brewed a UV exposure box for making PC boards ?
I've got a couple of 8w UV tubes & a 0-30min timer and looking at
pictures of commercial designs I think all I have to do is:

1. Mount the tubes & timer in a light proof box.
2. Fix a sheet of glass 1-2" above them to act as a flat mount for the
photo sensitised PC board & photo master.
3. Fix a mask to the glass, blanking off all but a working area directly
above the UV tubes.
4. Make a lid for the box & fit a foam pad inside it that'll press the
PC board and master firmly down onto the sheet of glass thus stopping
those sneaky photons from getting round the corners of the PC master.

Is it as simple as this or am I missing something blindingly
obvious ?? Is 1-2" a suitable spacing between the tubes & glass plate &
will normal, thin, glass sheet be suitable ??

I made my own from three pieces of MDF, some wood strips and a sheet of
glass. It's got the tubes etc. in the MDF base and two upright pieces of
MDF with two strips of wood acting as a shelf for the glass, about 9"
above the tubes, to give a bit of collimation. Glass is quite
transparent to the long-wave UV used for PCBs. I just put a book on top
of the board to press it down when exposing. I keep meaning to make a
proper lid with a foam pressure pad, but can't really see the point as I
don't use it much. It's some distance away, so I'm not bothered about
getting sunburnt. 8-)

Leon