Hi all,
Poured a bunch more time into photo etching PCB's. Got frustrated with doing negative resist, so I went and got some positive resist stuff, the kind that come with the film already attached, brand is Datak. Now I'm getting somewhere, I just made a TTL to RS232 converter using .024 traces and it came out great. I can see I can easily do SO packages, I'm whipping up a DS3231 breakout board to test that out. I might be able to get down to .01 with some practice.
What I've found so far is this:
When using a laser printer, print two copies and overlay them to darken the traces.
Make sure the toner side of the transparency is down and the shiny side is up. That makes a big difference.
Take all measures to prevent dust, grit or fingerprints on the transparency.
Make a decent light and hood. Hanging a bulb don't cut it. I made a nice reflector.
Make sure developer is between 100 and 110 deg. F.
Now that I'm getting decent boards, I can get back to the alternator control board that got me started (again!) making PCB's. That one is working on the breadboard, all I have to do now is finish the artwork and crank out a board!
Jonathan
