I built one years ago, using a high intensity industrial
hi-bay lamp and suitable ballast/transformer. The glass
envelope containing the fluorescent material around the
quartz uv source must be broken off (carefully!) leaving
only the quartz tube. This gives a high intensity UV lamp
that is very long lived. Mine was built in the mid 1960's
and the original tube is still going strong. The lamps are
designed to run 24/7 for several years at a time. The only
drawback is that it requires a relatively long
turn-on/warmup time - like about 5 minutes for full
brightness. You need a mechanical shutter - a sheet of
plywood, aluminum, etc., to block the light between
exposures. And VERY good eye protection.
Norm
Terry Mickelson wrote:
> I'd like to build a UV box to do positive resist exposure. The
> presensitized boards are 5 by 7 inches, so the box and lamps need not
> be too large. Also not too hot as this box is only open on the bottom.
> LED's are under consideration but so far a pre-made PC board to hold
> 400 or so is too expensive. The board is nothing more than etched
> parallel lines with drilled holes every .1 inch. UV lamps are a second
> choice but they tend to fade and burn out over time.
> What are your recommendations?
> Terry M
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> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> Yahoo! Groups Links
>
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