Making your own PCBs on the cheap, easily!

["Ian Lowe" <ianlowe@xxxxxxxxxxxxxxxxx>]

Okay, I had one of those little discoveries tonight that just has to be
shared...

I know that a fair few folks on the list do some electronics dabbling at
various levels - and like myself make up simple PCBs in house.

Previously, the best and easiest way that I have found to make PCBs
reliabl=
y
was using a special blue paper/film that Maplin sell - you make your PCB
layout in something like Eagle CAD (the freeware version is pretty good for
small stuff) then print it on your Laser printer.

The pattern of the PCB is transferred onto the film, which you then iron
onto a blank copper board (which are buttons from Maplin - a huge one that
=
I
managed to get a good ten or so circuits out of only cost =A32.50). I
prefe=
r
these blank boards to the UK sensitised ones, as they are a fair bit
cheaper!

Once the pattern is fully burnt onto the board (the toner melts, and
re-fuses onto the copper), you can etch the board - again, the chemical to
do it (Ferric Chloride) is sold pretty cheaply from Maplin.

The expensive bit of the process is the film - it's =A315 for three
sheets.=
..
So you end up running it through the laser lots of times, with the PCB
design aligned a different way each time.. Which means that the quality
drops etc.

So.. Tonight, I bolloxed up my last bit of film - there was a print job
waiting as the printer had run out of paper, and I printed a generic letter
out onto =A35 a page PCB film! :(

I spotted a pile of Photo paper beside the printer, and thought - what the
heck, it's a shiny surface.. It *might* work...

Surprise surprise... The cheaptastic kodak inkjet photo paper does the job
just as well as the proper PCB film - I printer my design onto it, and the
stuff came out of the laser printer seriously hot, and a bit tacky... Cut
out the PCB shape, ironed it onto the blank copper (it smelt a bit funky,
and melted the backing paper a bit)... Gave it 2-3 minutes on high heat,
then stuck the copper under the cold tap.

Sure enough, as the paper started to peel back (you have to be gentle
obviously) it left a perfect impression on the copper. The effect was a bit
like those "tatoos" you used to get in kids sweets that
transferred to the
skin when wet.

I etched the board up, and sure enough - perfect result! Except, of course,
that the photo paper was about =A35 for 25 sheets - much cheaper!

I'm guessing that it wouldn't work on "proper" laser photo paper,
as the
inkjet stuff seems to have a plastic skin for the ink to stick to without
beading.