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Dry film, photo resist - progress and question...

2008-10-25 by lcdpublishing

Hi guys,

I got a chance to do some more experimenting with the dry film photo 
process.  I did a "step" test doing various exposure times and found 
out that the UV lamp I bought for this purpose simply isn't powerful 
enough.  I have a regular light bulb of the right color range and 
tried that with much better results - exposure time through 
transparncy of only 3 minutes.  I have much more experimenting to do 
to get it better, but was able to make my first board all the way 
through the etching process.

A couple of questions...

1) When I used to have a black and white dark room, I discovered 
that the developer would last a long time and could be reused over 
and over again.  I realize the developer for negative resist film is 
much different than photographic developer, but suspect that the 
chemical will stay "active" and as such, I could be reusing it.  Has 
anyone tried this?

2) While doing the exposure / developer tests, I realized very 
quickly just how tough this resist is.  I was scrubbing with a 
scotch brite pad vigorously without removing the resist. This leads 
me to the next question. Should the resist be removed or can it be 
left on the copper?  If you have to remove it, how do you do it?

Thanks in advance!

Chris

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