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

----- Original Message -----
From: "Norm Stewart" <w6nim@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, October 15, 2006 1:36 AM
Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure


> I've used a 400 watt hi-bay lamp (480V ballast) without an envelope
> since 1973 - same bulb still going strong. Just keep it in a complete
> enclosure with a slot to insert the PCB sandwich.

The high-power exposure units use special "short arc" lamps, which emit a
lot of UV at the correct frequency. They give a very intense point source,
which is ideal, but are not very easy to use having very high trigger
voltages and high operating temperatures. They can also explode
unpredictably and have a short life. It would be nice to have one of those,
but they are simply too dangerous, even for me. 8-)

Leon