Using a 2.5kW CO2 laser you could probably directly cut the copper layer of the PCB without any need to etch it!
What kind of paint do you use as a resist?
>________________________________
>From: Jeanette <jdwalton@...>
>To: Homebrew_PCBs@yahoogroups.com
>Sent: Friday, July 8, 2011 4:49 AM
>Subject: [Homebrew_PCBs] Re: Laser cutting for DIY PCB
>
>
>
>We use a 2.5kW CO2 laser for embossing -- in our application it's very important to use a ventilator -- elsewise the "contrastiness" is impaired -- just as if you were using a camera with a dab of finger grease on the lense.
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