Homebrew PCBs

I don't have any problem routing between IC pins. Usually use 8 mil 
traces and I use rectangular pads 70 mil across the IC and 40 mil 
along it - gives extra space between pads while still leaving lots of 
meat to solder into. Works fine with 50 mill circular pads too but 
its my soldering that worries me, not the etching :)

Having only recently started etching my own boards I can tell you the 
three things that seemed to have the greatest impact on the boards I 
made.

1) Overexpose! My kit says 6 minutes, I go 8-10. You'll have to 
experiment to see how long you can get away with. Underexposure makes 
development harder and you're much more likely to have an invisible 
film of resist left over, screwing up your etching. I was worried 
that overexposure would screw up my traces but, I've seen zero 
degredation of the developed image and a great improvement in the 
etched boards.

2) Brush the board while developing. At first I was scared to 
actually touch the board with my brush. I just used it to swish the 
solution around. Made for long etching times and a fair bit on trace 
undercutting (eating the trace from the sides - under the resist).

3) When the board looks developed - its not! Keep brushing for 
another minute or so - if you watch carefully you'll still see some 
coloured mist coming off the "clean" copper. Thats the invisible scum 
that can screw up your boards.

Of course you'll have to experiment a bit to get it right. Make a 
small circuit and repeat it several times over a larger board, then 
try things out. You'll likely lose a few but the gained experience is 
invaluable - like when you etch that 48"x56" 25000pin monstrosity!

--- In Homebrew_PCBs@yahoogroups.com, "Larry" <nettron1000@y...> 
wrote:
>  Hi folks. I was just looking at some of the boards in the 
> photo/files area and i must say thats very good work. None of my 
> homebrewed boards came out as good as those.
>  I was just wondering , How narrow can a trace be etched in a 
> homebrewed board? I'd like to know if anyone has tried running a 
> trace between the pins of an IC. The reason i ask this is because 
> there are times when the only solution to running a trace(s) is to 
> route them between the pads for the IC pins, can this be done?
> 
> 
> 
> Net.