Homebrew PCBs

I tried exposing some presensitized pcb using 100W household mains bulb 2 feet away from the board for 15 minutes.
I swished the pcb in developer for 5 minutes.  There was no trace of the image.  The same goes for household fluorescent lights. 

In bright sunshine I got a good image after 5 minutes exposure, the board etched fine.

Using a UV lamp of the correct wavelength and Wattage exposure time for me is 2 to 3 minutes.

If you have some left over pcb do a test. Use some cardboard and expose parts of a board for various times and try developing.

John G3UGY





From: D. Gareth Hughes 
Sent: Sunday, October 07, 2012 5:14 PM
To: Homebrew_PCBs@yahoogroups.com 
Subject: [Homebrew_PCBs] Re: recommend a dark room light


  
Hello,
The majority of Photoresist materials both positive and nagative are very much resistant to the usual artificial lighting, they require a specific wave length to activate [UV], there is a small percentage of UV in daylight tubes and bulbs so it would be advisable not to take too long when preparing a board for exposure otherwise no special considerations need to be taken, except don't do it outdoors in the sun!!
regards,
David 


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