Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

I'm new here but find this list very interesting. A good UV lighting
system is the plain old mercury vapor lamps. These are commonly used
for dusk-to-dawn lighting. The bulbs are available in several
wattages such as 175, 400 and 1000 watts. One of these bulbs and a
reflector makes a great UV exposure system. Visit any large warehouse
and check out the lighting system since these are very commonly used
in larger buildings.

I have a commercial exposure system that uses this type of bulb. It
is a Colight Model DMVL-930 with 1000 watt bulbs on the top and
bottom. The exposure time when using 1.5 mil dry film photoresist is
17 seconds. If there is any interest in this I can photograph the
"guts" of this machine next time I clean the reflectors and post the
photographs in the photo section of this list.

It really would not be hard to make this exposure unit. Polished
aluminum sheeting or aluminmum foil could be used to make the
reflector system. I have helped several of my ham buddys set this
type of unit up and they have all been amazed at how fast this can
expose the photo resist. You can also make silk screens with this
setup.

I made my first hobby circuit board in 1966 and owned a commercial
printed circuit business for 23 years. We closed that plant last year
due to foreign competition and rising costs. I did keep the best
"small" equipment for my own home shop. This still allows me to make
boards for the instruments I make as well as my ham radio projects.

We gave away the plating operation because it was really a drag
putting up with the evironmental issues etc. I kept one smaller
photoplotter, several semi-automatic drilling machines, silk
screening equipment and all of the tooling and setup stuff. The big
Excellon CNC drilling and routing equipment was all sold off.

I started my company on the kitchen table in the late 1970's and it
looks like I've gone full circle but this time ended up in the
basement! It's much more fun this way I might add. We made boards up
to ten layers back then but it was just way to much work and the
headaches just kept getting worse. Too much work, too many hours, too
little pay and no more fun !!

I do enjoy the hobby side of this technology and would be willing to
help out with ideas and maybe some equipment projects that could be
posted on this list. If there is any interest let me know. Sorry
about the long post... sometimes I get going and don't know when to
stop!!! Hope I can help out.

Tom