"Peter Johansson
rockets4kids@... [Homebrew_PCBs]"
<
Homebrew_PCBs@yahoogroups.com> writes:
> 1. 30% HCl works brilliantly for cleaning any tarnish off a board.
> Just wipes it right off like magic.
That's because the tarnish is copper ∗oxide∗, and as I mentioned
earlier, HCl needs an oxidizer - so it etches the copper oxide but can't
etch the copper. Be careful, though, HCl is a nasty chemical to work
around. Note that copper oxide is also one of the possible starters for
a CuCl etchant - which ∗will∗ etch copper.
Me, I use a green scrubbie. Prepping a board for TT or UV is more than
just cleaning the copper - you need to make a mechanically rough surface
for the toner to cling, and the scrubbie does that. Toner won't stick
well (or at all) to a mirror finish (which is why it releases from
transparencies).
> 2. It is ridiculously easy to tin your entire board using nothing
> more than a broad-tipped iron.
Unless you're doing fine-pitch surface mount parts, in which case the
uneven surface of the solder messes you up a lot.
Liquid tin is a lot easier to do, too, and you don't risk lifting the
copper traces off the pcb.