[Homebrew_PCBs] The way I do it
2001-12-06 by Paul Waller
Hi all,
I have just joined this group and thought I'd share the method that I use
to make PCB's. I have used a variety of methods over the years beginning with
Plastic tape of 2 different colours on drafting film being double size and
photographed using filters to separate the two colours and creating 2 negatives,
then coating blank pcb with photoresist and drying then exposing and developing.
It used to take ages to get a pcb from a design. Then when the design
didn't work..... (Boy, did I really do all that!)
Now I use Protel Autotrax and simply print to a laser printer which I use
as the positive phototool and I spray CRC onto this (as recommended by a screen
printer) which makes the paper more translucent. I allow this to dry under a
heat lamp, line up the two sides on a light box and tape them together. I then
use KINSTEN positive acting PCB material which has a green coating and is very
cheap (about $3.00 U.S. for a 100mm x 150mm sheet) I made a light box with a
double fluro batten top and bottom using 4 x Philips TL20W/05 tubes and a
central shelf with the centre cut out with a jigsaw. A couple of sheets of
window glass which I place the pcb/artwork between. Expose for 12mins and
develop in Sodium Metasilicate or KINSTEN DP50 developer (also very cheap) and
etch in an Amonium Persulphate Solution in a KINSTEN tank with air bubbles from
an aquarium pump. Voila! A very quick and amazingly accurate way to make
prototype pcb's. I use 15 thou tracks min but could probably go thinner.
I have never tried the direct toner to pcb method but after reading from
this group might give it a go.
Regards,
Paul Waller
University of Tasmania
Australia.