Homebrew PCBs

I appreciate your response. I did notice that the default size of 
vias in Eagle is kind of small and leaves no room for error. I 
bumped them up to 15mil pads. Most of my lines are 10 mil and space 
between is 8 mil. The single sided boards that I've done came out 
99% good, except a minor line being broken but fixable. When you do 
a dbl sided board do you use defaults in the routing parameters or 
do you change them and favor 1 side to give less traces on the top? 
What is the smallest drill bit you use? Do you "tin" the board when 
finished etching?

Thanks!



--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> 
> Its not hard at all to get good registration with double sided 
boards.
>  I dont even bother making single sided anymore.  You need to take
> care when ironing to ensure that the paper doesn't move.  When I 
was
> using an iron, I would tack in the middle and work outward.
> 
> In terms of line width, I can do 10 mil pretty easily though I 
prefer
> 12 mil.  You can get 12 mil through 100 mil pitch parts and it 
stands
> up to the vagaries of the etch tank a little better.  
> 
> Yes, I use wire in the vias and solder both sides.  I'll use what 
ever
> wire I have that's scrap.  Since I got a couple hundred feet of 
scrap
> cat5, I've been using that.  28 ga, I believe.  I thread the wire
> through all the vias and solder them in one pass on each side of 
the
> board.  I then use the wire loops for continuity testing and clip 
them
> off as I determine the via is good.  Its a good, cheap and fast 
technique.
> 
> I know that others use eyelets but my one experiment with them was 
a
> mess and I wound up chucking the board.  You need to make your vias
> pretty big (much larger than the eagle default).  
> 
> The biggest issue I have is via placement.  Since I use a wire to
> complete the via, one can't be put under parts that are flush with 
the
> PCB.  Also, you want to be careful not to place a via too close to 
a
> pad as the heat of soldering the pad can cause the via wire to drop
> out.  I suppose if you use eyelets, some of this can be overcome.  
I
> generally dont put vias under things as it allows me access to go 
back
> and touch it up if I muffed the soldering.
> 
> Have fun!
> 
> Phil
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Bob Weiss" <BWeiss@p...> 
wrote:
> > 
> > Using the "Staples Paper/Ironing" method, what are the best 
> > achievable results you have gotten for a double sided board? I 
mean 
> > what are the thinest lines (in mm or mils) and space between 
them. 
> > The reason I am asking is because I just designed a double sided 
> > board that is pretty complicated (I use Eagle Pro) and I don't 
want 
> > to waste my time if it can't be done at home. I have done single 
> > sided boards before with this method and have gotten great 
results. 
> > The best I can get this particular board to route 100% is if I 
use 
> > alot of via's. If I go with a 4 layer and send it out ($$$) then 
its 
> > not that hard to route. Just trying to get some your prior 
> > experiences and see if I should proceed. Thanks for taking the 
time 
> > to reply.
> > 
> > Also when dealing with vias how do you solder them? I was 
thinking 
> > of using thin (30 guage), bare wire and solder it on both sides 
of 
> > the board. Does anyone have any better ideas?