Homebrew PCBs

On Thu, 07 Apr 2005 18:43:48 -0000, samIam <asa386@...> wrote:

>
> I was thinking that I could
> 1) use a double sided copper PCB and try and align the holes
> or
> 2) use a TWO single sided PCB's ... transfer,etch and drill
> then glue the two together before soldering and filing in vias
> I am leaning towards the latter because it appears it will produce
> the best board ... although it may take time ... drilling so many
> holes.
> Any ideas
> especially from personal experiences.
> Thanks in advance


I do not see ANY advantage in using two boards if you don't want more than  
2 layers.

The main problem with alignment for me is not to get thigs aligned over  
each other but laser printer distortions.
(Meaning no matter how often you shift things around there will never be  
all areas 100% aligned.)

Now making 2 boards doesn't make that better in any way.


If you have trouble with alignment, the following works for me:

You need your layouts with a added border of about 3-4cm on one side (the  
same side on both).
You also need a sheet of thick paper / thin cardboard, which you fold over  
in the middle.

First you take your two layouts, put them together toner side and hold  
against a light source.
Now move around until aligned as good as possible. when fine hold them  
with one hand (my right one) on the opposite side of the excess paper.
In the other hand (left) take the folded piece of light cardboard. Open it  
and put the aligned layout in, with the excess paper up against the folded  
edge. now hold it all together by gripping the folded edge of the  
cardboard (left). This frees the one hand (my right) to put in the PCB  
between the two sheets of layout. now hold together by pressing where the  
PCB is and let go the left hand. Feed into the fuser with folded edge  
first or iron (if iron i suggest a different procedure, see below).

When using this alignment method for making one side copper and one side  
component legend make SURE YOU PUT THE COPPER ON THE COPPER LAYOUT SIDE  
WHEN PUTTING THE PCB IN. Can't tell you how often i get this step wrong  
and end up with conductive component legend... ARGH...


Ok, if you use a iron there is another version i used. On the excess paper  
side make a 1cm wide strip of solid toner on both layouts. After alignment  
use your iron to fuse this strip together, taking care not to heat the  
rest of the layout. You can even make a pocket with a "tack" strip on  
three sides. Then simple slide the PCB in and iron both sides. (Might need  
to tack first for all-out ironing could weaken the fused edge(s) and allow  
sliding when turning over.

ST