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

previous by date index next by date
previous in topic topic list next in topic

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

From: DJ Delorie <dj@...>
Date: 2009-06-02

Philip Pemberton <ygroups@...> writes:
> (using Thinktink's numbers as an example) Dry film requires 42.5 mJ/cm^2

ThinkTink's film requires 150-300 mJ/cm2

> Double that = 1307.58 seconds exposure

That's 21 minutes. Sounds about right for an initial step gauge test.
I'd use 16 just to make the math easier ;-)