In a message dated 98-01-28 10:19:50 EST, you write:

<<
 Actually, the copper foil technique was developed precisely because it
 is easier than the heat transfer method, and produces vastly superior
 results.  It is very dificult for most people to get consistent
 results with the TEC sheets (and similar products), and the very fact
 that the toner is transferred twice limits the minimum reliable trace
 width.  This new method promises high quality prototype PCB's with a
 minimum of fuss.


 CIAO - Martin.
  >>
Hello Martin,
I admit that I haven't tried the direct foil method (I would like to someday)
but I have to take issue with the statement that the toner transfer method
limits reliable trace width.  I have spent quite a lot of time perfecting the
toner transfer method.  I routinely do double sided boards with traces down to
10 mil.  I will admit that I gave up on commercially available transfer
papers.  My company uses a silicon coated mylar for our casting machine
(www.dreitek.com if you are interested).  I cut the scrap rolls from our
ceramic casting operation into sheets and use that directly.
I also found that you never use an ordinary houshold iron to do the transfer.
It is far better to heat the board and NOT the transfer.  I use a rubber mat
heater controlled by an ordinary dimmer switch.  I get the board hott enough
to make the toner tacky but not so hot that it oxidizes the copper.  I use a
small paint roller to smooth out the pattern.  I let it sit and cook for about
10 minutes, and then I give it a final roll with the paint roller.  I remove
the board and the transfer from the heat and apply an ice cube to the top of
the transfer.  It falls off with absolutly no toner remaining on the transfer
sheet.  For double sided boards I transfer the top side pattern and then drill
two or more small holes that act as alignment for the bottom side transfer.
When I flip it over I have to use another sheet of mylar underneath to prevent
the other side from sticking to the heater.
Most of the boards I make use surface mount PIC based devices. and surface
mount components down to 0603 size.

Dave Duley