While I admire the creativity that people are showing, I am still
wondering why bother with these other techniques when the
photo-activated PCB material makes this method so easy?
I've used both laser printer and photo methods, and the photo method,
in my experience, is far, far easier and less trouble prone and
produces superior traces. I've done double sided boards this way and
the traces have been tack sharp.
I've heard complaints about needing a darkroom and special equipment,
but this is far from true. The pre-sensitized board I have used has a
light-resistant plastic cover, so you can handle the board in normal
room light. I've simply turned the lights down and not used
fluorescent lights (UV) and not had any problems.
The simple process is as follows (for single sided board):
1) print the PCB layout on an inkjet printer using high quality
transparency film. I've found the Pictorico film beats everything else
I've tried hands down.
2) lay the transparency over the sensitized board and put a piece of
glass over top. I got a set of 4x5" glass sheets from the place I got
the board from. It may be UV transmissive. I'm not sure if it's
special.
3) Expose. I use a simple fluorescent ring desk-lamp placed about 6"
from the board with an exposure of 7-10 minutes
4) Develop - this just takes a couple minutes in the developer
solution
5) Drill (I prefer drilling before etching to avoid ripping tracks
off)
6) Etch as normal
No ironing or soaking the board. The entire process has been quite
simple and a lot less frustrating than my experiences with iron-on.
I'm sure many of you have perfected the iron-on experience, and I
understand that it doesn't require any special boards, which is a
definite plus. But for under $15 for a square foot of pre-sensitized
board, it just doesn't seem worth the hassle.
The place I got my supplies was
http://shop.store.yahoo.com/webtronics/printed-circuit-board-supplies.html
(standard disclaimer: I've no financial interest in this company. I'm
just a happy customer)