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Subject: Re: [Homebrew_PCBs] Dry film- negative resist... First attempt failure

From: Michel Baguet <bagmik@...>
Date: 2008-10-20

With a negative film, this sounds more like under-exposure.
Have you tried increasing exposure time ?

--- On Mon, 10/20/08, lcdpublishing <lcdpublishing@...> wrote:
From: lcdpublishing <lcdpublishing@...>
Subject: [Homebrew_PCBs] Dry film- negative resist... First attempt failure
To: Homebrew_PCBs@yahoogroups.com
Date: Monday, October 20, 2008, 3:19 PM











Hi guys,



I tried my first photo process board this weekend and the process

failed completely. I am using the dry film, negative resist from MG

chemicals.



The failure was in the developing of the resist. While developing,

all the resist washed off. It was developed as I could see the

traces in the resist, but faintly.



The developer solution was a best guess on dilution so this is

probably my main failure point.



I am wondering what actually holds the resist to the board though.

Per the instructions, I am suppose to peel off the backing, apply

resist to the board and then run it through a laminator twice. Is

this what causes the dry film to stick to the board or is it the

exposure process?



I also suspect that using vellum for the artwork is not a good

thing. Using some scraps, I noticed that exposure is much different

using transparncy than vellum. So my next attempt will be using

transparencies and to carefully measure the developer.



Chris


























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