Homebrew PCBs

> -----Original Message-----
> From: Russell Shaw [mailto:rjshaw@netspace.net.au]
> Sent: 26 September 2006 12:17
> To: Homebrew_PCBs@...m
> Subject: Re: [Homebrew_PCBs] Re: UV Light Sources

> I made a UV lightbox with a 125Watt HID lamp (HPR-125) 24" 
> from the glass,
> and in a cylindrical parabolic reflector (lamp lays 
> horizontal). 90%+ exposure
> happens in 30secs, and i found a good optimum to use is 90secs for
> pre-coated negative pcb. The pcb is held against the glass by the lid
> that has a layer of sponge.
> 
> Without the reflector and beam collimation, you'll need a bigger globe
> for the same exposure time.
> 

Thank you very much for that information Russell. Points like your experience on the exposure time and distance between light source and object provide a real contribution to my knowledge base and, no-doubt, many others on this list on this matter.
Regards
John C