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April 1964 Radio-Electronics
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
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This 1964
Radio-Electronics magazine article provided a 12-step guide for creating
printed circuits at home, which involves gathering necessary materials,
designing the circuit layout, applying resist materials, etching the board, and
attaching components. The process could be laborious and often did not produce
satisfactory results (ask me how I know). However, modern methods have
significantly improved and streamlined this process, making it more efficient
and accessible. Today, low-cost prototypes
can be easily obtained from various online sources, allowing hobbyists and
professionals alike to create high-quality printed circuit boards without the
need for extensive manual labor or specialized equipment. These advancements
have revolutionized the way we approach circuit design and production, making it
easier than ever to bring electronic projects to life.
Printed Circuits for Everyone
 By Carl Henry
Twelve steps to easy miniaturization-right on your own workbench
 1) These are materials you'll need for etching
printed circuits. From left, copper-plated phenolic boards, available in sizes from
9 x 12 inches down. Resist material is available as paint, tape or ball-point pen.
Etchant (large bottle) can be purchased in 6- to 32-ounce bottles. It will keep
indefinitely, and 16 ounces will etch 100 square inches of copper-plated board before
being exhausted. Eyelets are available to fit the boards. At right, prepared board
with several components beside it.
 2) After you decide on circuit you want
to construct, the first step is to layout etching pattern. It may be necessary to
draw several designs to obtain the most efficient layout. You may have to use a
board with plating on both sides, since, unlike regular wiring, etched wiring cannot
cross. Make a circle 1/8 or 3/16 inch in diameter at each point where a wire will
be attached or a component mounted.
 3) Typical ways of mounting components to
printed circuit boards. In (a), resistor is mounted perpendicular to board - takes
little surface space; (b) shows same resistor parallel to board, which reduces height.
Conventional axial-lead capacitor mounts as in (c), special printed-circuit type
as in (d). Small transformer tabs can be soldered directly to unetched areas of
board (e); leads run through holes. Typical small-signal transistor goes in as shown
in (f), tube socket (special printed-circuit type) as in (g). Mount "top-hat" diode
as (h).
 4) Once you settle on the final layout,
trace it onto the copper-clad board with carbon paper. Tape down the board, carbon
and design to prevent shifting. If the board has a copper plate on each side, two
designs will have to be drawn, and you will have to be careful to see that they
do not conflict.
 5) Here are typical printed-circuit layouts
for simple devices. In (a), a one-stage audio amplifier with transformer output.
Note rectangular areas of copper foil left for soldering transformer mounting tabs,
as shown in Fig. 3-e. In (b), a differential dc meter amplifier and its layout.
Large circles surround holes that fit right onto meter terminals, providing mechanical
mounting as well as electrical connection.
 6) Next, resist is applied. Etchant will
not react with resist, and so copper underneath is not removed. Paint resist is
easiest to apply for circles (to mount eyelets) and large areas. Tape resist is
neater and easier to apply for lines. Special tape of proper width can be purchased,
or plastic electrical tape can be cut to desired size.
 7) Etching the board comes next. Heat the
etchant gently, in a Pyrex glass or beaker, to speed the process. A 10-square-inch
board can be etched in about 15 minutes with a fresh solution. Excessive heat will
cause etching solution to give off white, acid-smelling fumes.
Etchant is composed of nitric acid and ferric chloride in water. In small quantities,
purchasing ready-made etchant is cheaper than mixing your own. Also nitric acid
in concentrated form is very active and very dangerous to handle. Never attempt
to etch with concentrated nitric acid. A violent reaction will occur when the copper
board is added to the concentrated solution.
 8) Etchant removes all copper except that
protected by resist material. After etching, resist material should be removed.
Tape resist can be pulled off, paint resist can be removed with turpentine. In both
cases wash the board thoroughly with an abrasive kitchen cleanser and rub dry.
 9) A circle has been previously made (Step
2) at each point where a wire or component is to be attached. Now you drill a hole
in center of each circle, using a No. 52 drill. Be careful not to bend the board
from this point on, since even a slight bend may break copper foil.
 10) Insert an eyelet (rivet) in each hole.
Turn board over and spread eyelets with center-punch. Then use pin-punch or small
hammer and carefully complete spreading. Tap board gently, and be very careful not
to bend it.
 11) Attach
all components by running their leads through eyelets and soldering. Allow solder
to cover eyelet and contact copper plating. Heat sinks should be used when soldering
transistors or diodes. You can make an efficient heat sink by sweating two pieces
of copper into the jaws of an alligator clip. Attach clip between components and
solder joint, with copper in contact with wire. The copper will absorb the heat.
 12) For
a very permanent job, put the completed board in plastic box, or make a mold around
it and cover it with epoxy resin. Circuit will then be resistant to moisture, shock,
breakage, acids and most anything else except component failures from overloads
or misuse. Use epoxy sparingly. Once it is used on a board, nothing further can
be done to the board if repairs are necessary.
Complete kits for etching circuits are available from Lafayette Radio Electronics
Corp. and from Allied Radio Corp. Prices range from $3.75 to $27. Parts of these
kits are available separately.
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