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?