Re: gEDA-user: Do it yourself PCB's via heat toner transfer.

[Dan McMahill <dan@mcmahill.net>]

On Sun, Nov 07, 2004 at 10:25:23AM -0500, Syed Faisal Akber wrote:
> 
> As far as the heat transfer stuff goes, a friend of mine tried out many
> scenarios.
> 1 - Special Transfer paper --> Some of the paper that didn't have toner on
> it got stuck to the copper clad.
> 2 - Regular what 20# paper --> Same results
> 
> He's now using photographic echant processes now.  I guess there must be
> varieties of the transfer paper.  Unless you get the right one, it is just
> a waste of money.
 
There are a couple of varieties.  There is one which looks a lot like paper
with a shiny coating on 1 side.  I found that didn't work so well.  There is 
another product which has a blue colored coating.  That seemed to work much
better.  The blue coating contains some etch resistant material and places
where you print on the blue coating actually peel off onto the board when
you iron it on.  It seemed to work quite a bit better.

To echo the words of some others though.

1)  Clean the board

2)  Clean the board again!

3)  Keep your filthy fingers off the clean board!

Also, some experimenting with iron heat, pressure, and time for ironing
was needed.

As far as regular laser paper, I've used that too, but you end up with lines
which are not as crisp and you can have tiny little shorts on the board where
some fiber from the paper stuck to the board and prevented complete etching.

The last thing I'd mention is a heating tank and agitator seems to help
with the etching.

After all this, the conclusion I've reached is that there are vendors who will
do small 2 sided boards cheaply enough that I no longer care to mess with 
the headaches of a photo transfer or heat transfer step and the concerns of
chemicals and proper disposal of them.

-Dan

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