Homebrew PCBs

Any help or tips on etching double sided boards?
I want to etch a double sided board, nothing to complicated.
I have etched before using laser transfer method with success,
just after some tips for lining up.

Alan.

By lining up, I assume you mean aligning the two pieces of paper that 
have the transfer patterns printed on them.

I use 24 lb paper for printing the toner on and a light table to 
align the top and bottom papers.  You can use a sunny window or a 
slide sorter in a pinch but a light table is the easiest.  Also, I 
use double sided tape from 3M that comes in a handy little 
dispenser.  Most office products stores carry them.

Using my layout SW, I draw an outline around my layout before 
printing.  This serves to allow me to line up the two pieces of 
paper.  

I tape one piece of paper, toner side up, on the light table glass.  
Then I place the second paper, toner side down on the first paper.  
With both hands, I slide the top paper around until I get good 
alignment.  Holding the paper in place with the heel of one hand, I 
lift one side of the top paper and hold it with the fingers of first 
hand (one hand both holds the paper down to preserve alignment and 
one edge of the top paper).  With the other hand, I quickly lay down 
some of the double sided tape on the bottom paper about 2-3" from the 
edge of the artwork.   Then I lay the edge of the top sheet back down 
and smooth it so the two pieces of paper stick together.  I recheck 
the registration to make sure its ok.  Then I tape the papers on the 
opposite edge from the first tape.   Next, I cut it out so there are 
about 3" all around the artwork.  This makes a sandwich that I can 
slide my prep'd blank into. I also use the light table to get the 
blank aligned.  I use forceps to slide the blank in and tweak the 
alignment

At this point you can feed your board through a laminator, fuser 
assembly or iron it just like you would for a single sided board.

Be sure not to touch either the toner side of the papers or the PCB 
blank with your fingers.

Preserving registration can be tricky with laminators.  I've been 
using a carrier when feeding the board/paper assembly through.  
Childrens construction paper makes a good carrier.  Some one here 
gave me that hint and it really works well.  There are other schemes 
that, no doubt, will work but I haven't tried them.

Making a light table is pretty easy and cheap.  I think I paid less 
than $15 total for the material for mine.

--- In Homebrew_PCBs@yahoogroups.com, "ginettaman2001" <pcpro-2@b...> 
wrote:

> 
> 
> Any help or tips on etching double sided boards?
> I want to etch a double sided board, nothing to complicated.
> I have etched before using laser transfer method with success,
> just after some tips for lining up.
> 
> Alan.