I've tried out Chucks's suggested paper, and a couple of
other re-purposed alternatives. they certainly work, but
it took a while to soak off, and I always had trouble
cleaning off the paper residue that remains stuck. For a
while even I tried working with the "Press'N Peel Blue"
plastic transfer film (more costly, but at the time it was
on the boss's nickel). But I was convinced on the spot the
first time I used the Pulsar paper stuff and saw it just
float off the board in about a minute, leaving nothing but
toner and clean copper behind - ready to pop directly into
the etch bath.
The raw deposited toner has some porosity and pitting can
be seen under magnification. Not nearly enough to be
damaging unless traces are really thin. Recently I've
started using the"Toner Reactive Foil" product as well and
find a much cleaner surface to the un-etched copper and
ability to get consistent traces down under 10 mils. The
foil pretty much eliminates the pitting.
Now, for DIY, I just about never use traces smaller than
15 mils, but some of the text legends and such that I'll
etch for ID will have lines of 6 or 8 mils, and they
usually come out clean.
If you were going to do a "mini mass production" of maybe
a few dozen boards (I did that once for a club kit - never
again, the drilling was a drudge - hi), a more economical
alternative paper is not a bad idea. But nowadays my DIY
boards are just about always one-off, Then if it turns out
to be a useful project that others might have interest in,
off it goes to a fab house. Nick and I will talk about the
"gotchas" for that process. There aren't many, but they
are important..... ask me how I know :^))
If you like Pittsburg style, or SMT, where drilling can be
mostly avoided, the DIY route is really attractive, even
for modest quantities.