Homebrew PCBs

"dagmargoodboat" <dagmargoodboat@...> writes:
> I don't think that's super critical for signal traces--as long as the
> trace exists & survives etching without breaking; we don't care if
> it's a little wavy.

I was thinking that less waviness in the print gives you more leniency
elsewhere.  At least, my prints don't have a definite "edge", it's
more of a 3 thou wide blur.  So I can't tell in advance where the edge
of the copper will be.

But if the mask is the issue, wouldn't inkjet+photomask be able to be
done at finer resolution?  Or do they still have issues with "fuzzy"
edges?

> > * Thinner copper?
> 
> Maybe, but why? (for high currents?)  Could electroless plate it up
> afterwards--that's not hard.

I'm thinking less side-etch, allowing you more time (relatively) to
over-etch everything else.  What I mean is, "in the time it takes you
to go 150% of the copper etch time, the side etch is still much less
than with thicker copper."

For example, when I etch 5 thou brass, I can't do a 5 mil space
between pads because the sides etch all the way across under the
resist.

>   I've just done my first experiments with magazine paper at 0.010"
> traces and spaces.  I found it transfers and releases *much* better /
> more completely than the inkjet paper I had been using.

I'm using Pulsar's paper, which transfers just fine, but the original
has a "fuzzy" edge, which results in variations in line widths.  The
2550N has a number of software knobs to fiddle with, but I haven't
been able to get any of them to make any noticable changes in the
actual print.

> (Preliminary reason seems to be, in part, the magazine paper is
> thinner, allowing better heating of the coppper foil underneath it
> when passing through my laminator.  A hot air gun also helps keep
> everything at temperature.)

I often pass the board alone through the laminator a few times to warm
it up.  I have some 8 and 16 thou SS on order for some
experimentation, I know I can't get a good transfer with 62 thou
phonelic as it sucks up too much heat from the laminator.

I've never tried magazine paper.  I suppose that's at least free to
try, but the TT paper releases so well...