But the most serious problem has to do with the fact
that ham radio operators learn to solder shortly after birth, or even
before... according to some.

So that's what my mom was screaming about two months before I was born --
internal solder splashes {;-)



MAKING THE CIRCUIT BOARD

WEll, you just blew my August Kitplanes article out of the water.



The Old Fashioned Way was to start with a drawing then go to litho
film, then to a fine-meshed silk screen. Once you had the silk screen
you could whip out a hundred circuit boards in an afternoon... after
spending a month to arrive at that point.

Nowadays I simply print the circuit board mask onto cheap
glossy-finished color photo paper using a monochrome laser printer.

And after many experiments, Staples Photo Basic Gloss (#471861) is my
candidate for the best.


But the paper
HAS to come apart if we want to leave ONLY the thermo-plastic material
bonded to our circuit board. So use the cheap stuff. And soak it in
warm soapy water. Then scrub it with a tooth brush or whatever -- get
ALL of the paper off of the thermo-plastic.

One of those green kitchen pot scrubbers does a pretty fair job getting the
paper off while leaving the toner on the board.



Now you can etch the board in the usual way.

Or you can use the new, improved way without that nasty ferric chloride.
Plain old swimming pool etchant (muriatic acid -- 28% HCl) from the home
store plus plain old hydrogen peroxide (3%) from the drug store mixed 2:1
respectively does an admirable job at room temperature. Plus, when you get
done, you have metallic copper (not a hazmat), hydrochloric acid (not a
hazmat), and the hydrogen peroxide which, within half an hour, has broken
down into oxygen (which has escaped into the air) and water. If you want to
be totally environmentally friendly, you can neutralize the HCl with baking
soda ($5.99 for ten pounds at the Charlie's Club places) before pouring it
down the sink.

If you wanna get fancy, go down to the discount pet store and get a 5 gallon
aquarium, a small aquarium pump, and a long stone bubbler. Bubbling around
the board cuts the etch time in half.



And having etched it, you
gotta drill those zillion holes. Once etched & drilled, remove the
thermo-plastic, which you can do with MEK or other kidney-killer
solvent and a bit of steel wool.

Please don't use steel wool. It embeds into the copper and helps
galvanically corrode the board. Let the board soak in the MEK for an hour
and it will wash off with the aforementioned green pot scrubber.



The result is a bright copper circuit board

Made even brighter if you use Copper-Brite from the supermarket and the
aforementioned green pot scrubber.

You might also google on "Tinnit", which is a surface tin plating solution
that quite a few mail order houses sell. Copper will corrode over time; tin
will not. You toss the board in the Tinnit solution and it will plate the
copper with tin in a matter of ten minutes.

Jim