Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "derekhawkins" <derekhawkins@...>
> >It won't be even close. Pigment inks, maybe possibly, but not dyes.
>>If you also have a laserjet, hold up one of each to a bright light.
>
> Regardless of ink type, the density of laserjet print ∗∗on
> transparencies∗∗ will always be vastly inferior to inkjet print. Just
> about everybody knows that.

I don't know it, so I guess I'll have to prove it for myself. I'll run some
through the lab's densitometer later in the week.

>>They're icky, likely from over etching. Still working on that part.
>
> You're a prime candidate for switching if that bothers you because
> that's the characteristic signature of a TT board. It's due to hand-me-
> down toner....LOL!

I puzzled over this for a little bit, and it niggled at me as I hurried
through a small board so I would have something to scan. Could it be your
standards differ than mine? Higher? Lower? That doesn't seem right; quality
is quality. I'm used to commercially produced prototype boards. Certainly I
have no expectation my own boards will be in the same league. But laughably
inferior? No, that doesn't seem right. The first few boards were OK. Not
great; just OK. The holes aren't plated, and the pads could use a good
fluxing and tinning. But the copper itself was just fine, better than just
OK. And then it hit me, as I stared at the toner black traces staring back
at me from the rinse water. That's rather odd...

Pulsar sells a green sealing film to overcoat the toner. In my haste this
evening, I forgot to apply it. I had etched the board with only the toner
for a resist. Sure enough, wiping off the toner with Goof-Off left a behind
a mottled mess where there should be shiny copper. The trace edges were
pitted; and the SL3 pads were... just yuck. It would take a blind man to
miss the difference, never mind the microscopy.

Derek, I know now what you must be saying. Toner alone is not a very good
resist. However, combined with a sealing film, such as Pulsar's green TRF,
toner transfer is every bit as good as any other process. And it's fast,
too. As late as it is over here, I know I can just run off another one
before heading to bed.