Homebrew PCBs

Good day all.

Heres a question I am certain has been asked a lot:
What is the best way to make a double sided board.

First some background
I am a newbie who just completed his first single sided board using 
the
Toner Transfer method and etching chemicals/drill.

But that was JUST a practice board. My project is designed for two
layers (component and solder). 

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

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

> 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.

OUCH
Too much hassle.
But Ill try both methods and see. I just ordered 10 12x7 single side
copper boards to complement the 15 12x8 double side boards in my
possession (THANK GOD FOR EBAY).

Also ordered seven tubes of a bonding agent.

It should prove to be an interesting few days... after these items
are delivered.

On Thu, 07 Apr 2005 20:26:45 -0000, samIam <asa386@...> wrote:

>
> OUCH
> Too much hassle.
> But Ill try both methods and see. I just ordered 10 12x7 single side
> copper boards to complement the 15 12x8 double side boards in my
> possession (THANK GOD FOR EBAY).
> Also ordered seven tubes of a bonding agent.
> It should prove to be an interesting few days... after these items
> are delivered.
>


Sorry but my brain just doesn't bend around enough to accept gluing two  
boards is any less work that just doing it all at once.
You have all the disadvantages and difficulties with gluing and no gain  
whatsoever over making it doublesided.

Oh well, you must make your own decisions.

ST

--- In Homebrew_PCBs@yahoogroups.com, "samIam" <asa386@y...> wrote:
 
<snip> 
>
> I am leaning towards the latter because it appears it will produce
> the best board ... although it may take time ... drilling so many
> holes.
> 

Rather than drilling all the holes twice, couldn't you just drill a 
couple for alignment and the drill the rest after the boards have
been 
glued together?

Regards, Bob

> Rather than drilling all the holes twice, couldn't you just drill a 
> couple for alignment and the drill the rest after the boards have
> been glued together?

Ill try both methods and see which one produces the better result.

Its certainly not an issue of 
drill
drill bits
copper laminate
toner transfer
laser printer

All of which I have or have in abundance. Time? no, I am currently
surviving on 6 hours of sleep a day. ;)

samIam wrote:

> 
>>Rather than drilling all the holes twice, couldn't you just drill a 
>>couple for alignment and the drill the rest after the boards have
>>been glued together?
> 
> 
> Ill try both methods and see which one produces the better result.
> 
> Its certainly not an issue of 
> drill
> drill bits
> copper laminate
> toner transfer
> laser printer
> 
> All of which I have or have in abundance. Time? no, I am currently
> surviving on 6 hours of sleep a day. ;)
> 
> 
> 

   Iron side 1.  Drill two holes in opposite corners, put some for alignment if 
you don't already have holes near the corners.  Punch same holes in side 2 with 
drill bits.  Use two bits in holes to get in alignment and start ironing.  Take 
out bits and finish ironing.  Etch etc.

   Unless your board is more than 8 inches, keep the longest axis across the 
page.  More distortion in the paper pulling direction than the scanning 
direction on most printers.

   Works fairly well.

   Surface mounting everything and doing 1 side is about ten times easier 
though.  I haven't had a DIP fail yet because I didn't drill 14 or 40 holes and 
make the leads go through the board.

Alan