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Subject: Re: [Homebrew_PCBs] Setting exposure with a step gauge

From: Philip Pemberton <ygroups@...>
Date: 2009-06-03

DJ Delorie wrote:
> Looks like you got the exposure just right. Are you using some type
> of vacuum hold-down? I found I had to do something about that because
> the weight of the glass was insufficient to hold the film tight
> against the board.

The UV box has a vacuum pump built in -- there are four UV tubes in the
bottom, covered with a sheet of glass, then four in the top with a sheet of
flexible transparent plastic over them. When the timer is started, the vac
pump runs for a minute or so, then the tubes are struck and the countdown starts.

--
Phil.
ygroups@...
http://www.philpem.me.uk/