--- In
Homebrew_PCBs@yahoogroups.com, "alan00463" <alan00463@y...>
wrote: Will an inkjet printer make white?
Not any I've had here. :(
After getting a laser for PCB's, I'm finally realizing how much I
hated the inks. Even if I'm stuck to B&W, not having to constantly run
out of ink is well worth the loss.
I think the TRF is the safest way to go. It's only about 6 or 7 bucks
a roll. If they haven't already popped in, someone in here answered a
few questions for me a while back about it. They said it was more
powdery, so it wasn't ideal for dual duty as a replacement for the
green trace coating TRF, but should make good labels. Sorry I can't
recall exactly who told me (I always appreciate the help).
BTW- With the cutting, I've learned to go oversize on the initial
boards. I usually do almost an eighth inch all around with some layout
lines for subsequent trimming. I've had most of my trouble with
foolishly placing thin runs near the edges. I either eat too close to
them while trimming, or the board is of a slightly inconsistent
thickness near the copper burrs at the edge, and doesn't take as solid
of a transfer. It's also nice to have plenty of space around your
mounting or standoff holes, to avoid having screws sitting on, or
shorting anything, or not having enough board at the outside corners.
I've done scroll saw, and "score & snap" with utility knives and glass
cutters on boards with a few different substrates. It all works, but
lately I'll just clamp the board down to my workbench, under a wide
flat block of wood, with the edge hanging off the table. I then saw my
line with a hacksaw, or even a raw hacksaw blade, taking really light
strokes at a fairly small angle. This seems to keep the cut line
straighter, and minimizes some of the blade/board wiggle. As I near
the end of the cut, I'll raise it more perpendicular, to avoid wasting
board and cutting way beyond my stop point. I usually cut more on a
downstroke, and try not to press too hard. I think when I start the
cuts, I even do only downstrokes until the blade is stable. The board
wiggle and binding of the teeth in reverse is the main trouble,
especially with part of the board unsupported. Other than that, the
whole thing only takes a few minutes, and I've had to cut much harder
and messier materials in the past. I've got a tile saw here, and
diamond wheels for my radial, but it probably isn't worth the setup
hassle, unless I had to produce a whole sheet of boards (unlikely).
I'm not sure how the cutoff wheels do on a dry run. It's more of a
smooth "burning" action, which is great with the water, but it may not
be too safe without it. I had to wear a "leaf bag apron" for cutting
tile, and it sprays crap all over the place. My tile rig's blade also
sits at a fixed height, so with thin softer material like boards, it
seems you'd be even more likely to bind or screw something up, as
you'd be passing much more blade area. Could be different with the
fully coated wheel, but my saws will kill you for that.
I usually do my final trimming to the border lines with a belt sander
running parallel to the board edge, and then stroke a file downward
across them, at a shallow angle, to clean the copper burrs and level
the edges. A sander will eat board surprisingly fast, but they both
sort of work on each other simultaneously, so you're best to use an
old belt and not expect it to be much good afterward. I've also had
decent success just laying a full piece of coarse or medium sandpaper
on a heavy, flat board or bench, and just "slicing" the PCB
perpendicular across it, back and forth, as if trying to score or saw
the paper. Just keep your lines moving across the paper throughout, so
you'll usually have clean grit to work with. This does pretty well
when there's less board to remove, and I'll also do it with fine
paper, after the belt sometimes, to smooth or square the edges.
Hope some of that helps,
George