Steam your PC Boards
How to use ordinary copier paper for
Making Printed Circuit
By Daniel Wee, 9V1ZV
Since the beginning of my electronics
construction hobby, I've just about built circuits in every
possible way I could think of.
I still remember my early days when I actually had germanium
transistors screwed down on a block of wood. That was before
I acquired my first soldering iron. I then progressed to the
well- known "ugly" construction technique where component
leads were simply soldered together. Other methods I
remember include, breadboards, matrix boards which were
quite popular at one time, wire-wrapping, board-excavation
and printed circuit boards.
Of all these, I have found the printed circuit board method
to be one of the most satisfying and aesthetically pleasing,
so far. This does not mean that it was an easy method, in
fact, I had avoided circuits requiring printed circuit
boards until I had tried everything else, and there was a
good reason for this. There are also limits to what you can
produce yourself, for example, you will not have the
facility to fabricate through-plated boards or multi-layer
boards. For these, if you ever need them, its best to go to
the PCB manufacturer to have them made for you.
Like many, I had supposed, rightly, that the fabrication of
printed circuit boards was a tedious process, requiring a
lot of basic tools and equipment which I did not possess. As
such, the whole process of fabricating a printed circuit
board had remained pretty much a mystery to me until I
entered the field of radio electronics. I discovered then
that the parasitic capacitance and electrical properties of
other construction methods were simply unsatisfactory for
circuits operating in the RF regions. Thus began my quest
for the printed circuit board. The purpose of this article
is to briefly outline the various methods and steps of
producing a usable printed circuit board.
The whole idea of making a printed circuit board
is really a chemical process of removing copper from the
circuit board at the right places, in order to leave behind
tracks suitable for carrying current as required by the
circuit in question. Boards can be bought which come with
copper clading one or both surfaces, used for making single
or double sided PCBs respectively. A visual survey of the
board reveals an uninteresting copper surface with no holes
or tracks. The constructor must find some way of removing
the copper in order to obtain a circuit pattern which can be
used. One way to do this is by "excavating" the board with a
sharp cutting tool to remove the copper. This proves to be
an extremely tedious method and can only be used for the
simplest circuit patterns. It is sometimes useful for making
quick and dirty modifications to an existing pattern.
The standard way of creating a pattern, however, is by means
of a method known as "etching". Etching is a chemical
process whereby the unwanted copper is removed by a process
of reduction, a chemical reaction, which "corrodes" away the
copper. This is often achieved by immersing the copper clad
board into a solution of Ferric Chloride or Sodium
Persulphate (I think). Upon contact, a reaction occurs which
reduces the copper on the PCB to copper chloride which comes
off the board. Ferric Chloride has now become a controlled
substance in some places because of its toxic and
environmentally unfriendly nature and this makes it
difficult to obtain from the usual sources. Sodium
Persulphate is the substitute for Ferric Chloride but has
not arrived at the shops here yet. Either of the etchtants
can be obtained in liquid or in crystallized form. Nowadays,
they are rarely found in liquid form because of the high
rate of oxidation which renders the chemical useless. More
often than not, they come in the form of dehydrated crystals
which we mix with water to produce the etching solution.
This solution is then used to etch the boards.
If you have been asking yourself how the chemical can be
prevented from removing all of the copper, then you have
asked an appropriate question. There are a number of methods
by which this can be done. The whole principle lies is
preventing the etching solution from coming into contact
with the copper you wish preserved on the board. This can be
by means of a water-proof tape on the board, rub-on
transfers, marker ink, etch-resist ink, toner ink, plotter
ink or photo-resist. In short, any method that can protect
the board from the chemical solution is usable. Some methods
are easier than others, of course, and the method to use
depends on a number of factors, such as complexity of the
pattern you want to produce, the density of the tracks, the
boards available etc.
Once you have, for example, drawn a pattern onto the clean
copper clad board with etch-resist ink, you may immerse the
board into a properly prepared etching solution for the
etching process. This can take from 5 to 30 minutes or more,
depending on the concentration of the etching solution.
After that, the board is removed from the solution,
revealing a board where the unmarked portions of the board
has no copper on it, the board material beneath being now
visible, and the marked parts of the board still having the
ink in it. Once the ink is removed either by sanding of by
the use of solvents, the copper will become visible. The one
last remaining step is to drill the holes for component
leads in the right places and the board is ready for
That is generally what happens in the process of fabricating
a PCB. Time does not permit me to cover all the methods that
you can use so I will highlight some of the major steps in
the following text.
The Copper Clad Board
Boards suitable for etching can easily be
obtained from parts suppliers and come in a number of
varieties. Typically, there are two major types of board
materials that are used for the base board, fibre-glass
(glass-epoxy) and phenolic paper. Fibre-glass boards tend to
be tougher, look better and probably has slightly lower
surface capacitance properties, as well as being the more
expensive of the two. Phenolic paper, on the other hand, is
easier to cut and drill though it tends to crack or fragment
as it is more brittle, and cheaper. Both types can be used
for homebrew construction projects as the mentioned RF
properties are quite insignificant until VHF frequencies and
You will find single-sided copper clad boards as well as
double sided ones and you choose the type of board
appropriate for the circuit board you wish to fabricate.
Double sided boards are normally used for RF related
circuits because it offers a stable one- point ground-plane
which helps stability and prevents unwanted oscillations or
ground loops. However, producing double-sided PCBs requires
high precision tools and I will only briefly mention some of
the methods for producing simple ground-plane double sided
boards later. This should be sufficient for a start.
You will also come across boards which are "pre- sensitized"
or "photo-sensitized" which are used to produce photo-
resist patterns. These boards are typically much more
expensive than the plain boards because of the photo-resist
film that has been pre-deposited over the surface. Such
boards often come in light- proof wrapping with an
additional layer of opaque plastic on the board surface
which will not be removed until ready for exposure. I will
detail this technique below.
Before you get started with the boards however, you will
need to cut the board down to the size you need. Normally
boards are sold in several sizes so you may pick either a
large sized board and cut it up as you need, or select a
size that is closely matched with your required size to
minimize the cutting. The boards can be difficult or easy to
cut, depending on the material of the board and its
thickness. Average boards are about 2 mm thick and are quite
tough and difficult to cut. Some boards come in 1 mm
thickness and can be cut using a heavy-duty cutter. This
type of board is usually quite flexible and thus the bending
will not damage it. The thicker types on the other hand,
will tolerate little bending before fracturing or
fragmenting. Cutting can be achieved using a hobby saw with
a fine-serrated blade. Thick saw blades are not suitable for
this. Sawing should be done slowly and gradually in order
not to damage the board. Saw perpendicularly to the board,
which should be clamped down to the work-bench firmly using
a G- clamp or a similar device. Alternatively, you can use a
heavy-duty Exacto knife to engrave the border lines of the
appropriate size. When using this method, it is not
necessary to completely cut through the board. Once about
3/4 of the thickness has been cut, you can usually snap the
board along the engraved lines. It is important to engrave
BOTH sides of the board, otherwise you will not get a clean
break. This method is very tedious, time consuming and tends
to destroy your blade, especially when cutting fibre-glass
boards. It can be used when a hobby saw is not available.
Try not to scratch or damage the copper surface when doing
this. After the board has been cut down to size, use a
medium sized file to smooth out the edges for a nice
The Etching Process
The next most important component you require is
the etching solution. As of now, very few shops will sell
Ferric Chloride crystals to unlicensed buyers and Sodium
Persulphate is not publicly available. There is a good
reason for this but it means a lot of inconvenience for the
home constructor. There are means of obtaining the chemicals
which will not be detailed here.
Ferric Chloride is most commonly available as
dehydrated crystals and sold in plastic containers. It is
very important to keep these crystals in a dehumidified
environment as it tends to combine with moisture in the
atmosphere and turn into a really messy and staining liquid.
Be forewarned that this substance stains permanently on
clothes and even some plastics or ceramics, is highly
corrosive, carcinogenic and toxic. As such it should be kept
out of reach from children and water. For the same reasons,
it should not be discarded into the public drainage system
before diluting it with large amounts of water.
Sodium Persulphate is a white crystal and though it
is environmentally more friendly that Ferric Chloride is,
similar precautions should be taken and care exercised when
dealing with concentrated chemicals of any type. This
substance is considerably safer however. For one, it is
endothermic when dissolved in water and the resultant
solution is a clear and non-staining solution. It is also
slower acting than Ferric Chloride and probably needs more
agitation and perhaps a little warming up. A good way to
speed up the reaction may be to dissolve the Sodium
Persulphate crystals in boiling water. Take all necessary
precautions to avoid scalding.
The way to prepare the solution is to mix the crystals into
some water, usually 1 part crystals to 5 parts water. This
is just a guide and once you understand the process you can
easily produce higher concentrations to etch boards more
quickly. You should also be aware that the process of
hydrating these crystals is a highly exothermic one so do
not be surprised if the water starts to boil. As such, one
should NEVER throw any substantial amount of crystals into
the water. Similarly, one should NEVER add water to
crystals, always crystals to water. Normally, a plastic tray
suitable for immersing the circuit board is filled with
about 2 cm of water. The crystals are then added to the
water BEFORE putting in the board, using a plastic spatula
or any other suitable instrument. The instrument MUST be dry
before applying to the crystals. Never leave the crystals
exposed to atmospheric air for long. As soon as you have
taken out enough crystals, wipe dry the rim of the crystal
container and re- seal it in its air-tight container and
store in a dry place out of reach of children. Do not get
the crystals or solution on to your skin or eyes, and if you
do, rinse under cold running water to remove it. See a
doctor immediately in the event of ingestion. As you add the
crystals to the water, the water will change color, to dark
brown if using Ferric Chloride, and you should notice some
heat being produced. Do not be too worried by the heat as it
is useful for the etching process. Do not inhale any fumes
produced during the entire process, these are poisonous and
though in very small amounts, may cause asphyxiation
(Chlorine). All this should be done after you have readied
the board for etching. All instruments coming into contact
with the solution should be non-metallic. Stir the solution
until all the crystals have dissolved to produce an evenly
colored solution. Now the solution is ready for use. Try to
use it while it is hot so this step should always be done
after your board is ready.
Put your resist-masked board into the solution slowly so as
not to cause a splash. Remember that the solution is very
hot sometimes. Once the board is completely immersed,
regularly agitate the tray and pay attention to the exposed
copper. After sometime, the exposed surface will appear
dull, not necessarily evenly. The after more agitation you
will see patches of circuit board becoming exposed. Do this
until ALL the unwanted exposed copper surface has been
removed and the board material is visible beneath it. This
may not be easy initially as the etching solution may
obscure your view of the board. It is therefore good to have
a deeper tray which allows you to tilt the tray to expose
the board. Normally, surfaces with less exposed copper tend
to etch faster that surfaces with more copper, and once you
are more experienced, you may want to use a stronger
concentration for surfaces which require a lot of etching.
The copper corrosion normally starts from the edge of the
board and works its way to the center. Be sure to keep on
agitating the board so that the resultant copper chloride (a
powdery precipitate black in color) will get swept off the
surface. This will speed up the etching process.
While it is important to make sure every part of the board
is sufficiently etched, do not keep the board in the
solution longer than absolutely necessary. This is because
extended exposure will allow the etchtant to get under the
resist and affect the fringe of your tracks, resulting in
ugly patterns. Experience will soon tell you how long to
leave it in for the concentration you use. Normally
everything should be done in 25 minutes but it may be less,
depending on the size of the board, exposed surface, and the
concentration of the solution. Proper timing is especially
important when very thin running tracks are involved.
If you are doing double sided boards, you should at some
point, turn the board over. In this case, unless you have
special holders, you should not over agitate the tray as the
copper chloride precipitate which sinks to the bottom of the
tray is rather abrasive and may scratch off some of the
resist on the bottom side. Other than that, the procedure
remains the same.
Some of the shops sell special etching tanks which stand
vertically and has a little electric motor to automatically
agitate the tray. This is not suitable for small scale
productions as the tank normally requires large amounts of
etching solution to fill up, and cost quite a lot to buy.
For me, the above method is more than sufficient.
Drilling of Holes
The drilling of holes is typically the last stage
of the PCB fabrication process so this may seem a little
anachronistic. Nevertheless, this is the last common step of
the various methods of PCB fabrication so I thought it'd be
good to cover it now.
Clearly, you will need to drill the holes yourself if you
intend to put components on the board. In some
surface-mounted designs, especially common with microwave
and UHF circuits, this may not be necessary. Unfortunately,
you cannot use your trusty Black & Decker power drill
for this purpose because of the excessive speed of the drill
and the oversized drill bit. A hobby or hand-drill is
suitable and cheap ones, both battery powered and mains
powered, can easily be found in Singapore for under S$50.
You will need to get a few common small sized drill bits for
PCB use. The most useful by far is the 0.8 mm drill bit. The
1 mm and 2 mm drill bits also come in handy when drilling
larger holes on the PCB. Generally drilling PCBs do not
require a lot of effort because the PCB material is
relatively soft and easy to drill. Be sure to get spare bits
because the bits tend to break easily and are rather brittle
due to their small cross-sectional area.
You should position the drill bit perpendicularly to the PCB
for drilling any holes, and always maintain a steady and
firm grip of the drill. If necessary, you may want to use a
sharp instrument to slightly indent the spot you want to
drill, as a guide as sometimes the drill bit tends to spin
away from the point and scar the rest of the copper surface.
Usually though, properly made boards should have these
guides etched in. Do not apply undue force as this might
cause the bit to break or the board to crack. Apply a steady
force on the drill until you feel the penetration of the
PCB. It is also advisable to have a piece of unwanted even
wood surface beneath the board so that you won't destroy
your workbench or your drill bit. Soft-wood is best but
other soft material will also do, eg. old hard cover
Normally the drilling process produces a substantial amount
of debris which will obscure your drilling template. Thus
you will want to drill holes systematically so as not to
miss any holes inadvertently, and to drill a section at a
time, clearing away the debris as they accumulate. Do not
have the fan blowing while you are doing this or your XYL
will be all over you for messing up the place! Once you have
drilled all the holes, inspect the board for undrilled or
partially-drilled holes. Also be on the lookout for tracks
that may have come off as a result of the drilling. This may
sometimes be the case when drilling large holes on a small
pad. Remove burrs from the holes and then your board is
Masking the PCB
As was mentioned in the basic theory section,
there must be a way of controlling which parts get etched
and which parts of the board don't. I also briefly mentioned
a number of methods. Here I will highlight two of the
methods most relevant to us homebrewers. Direct penning onto
the board using etch resist pens and photo-resist.
Using Etch-Resist Pens
You can actually draw the desired tracks or
patterns onto the copper clad board with etch resist ink.
Get a normal copper clad board that has been cut down to
size, washed and dried completely. Do not soak the board in
the water for too long or the water may damage the board. Be
certain to make sure that there is not grease on the board
or oxidized surface. If necessary clean the board with some
mild abrasive to obtain a shiny surface. Avoid touching this
surface with you fingers or dirtying it. This will ensure a
more even etching later on. There is no need to specially
buy etch-resist pens for this purpose though you could do
so. For simple purposes, permanent markers or Indian ink
seems sufficient for the job. There are advantages and
disadvantages of using such a method. On the plus side, this
is a very convenient method for producing one-off, not too
intricate or complex patterns, and can be done rather
quickly. However, you cannot obtain high resolutions tracks
or any degree of evenness with this method. The results tend
to look amateurish. Just as a reminder, the tip of the
etch-resist pen tends to dry up quite quickly so the pen
should be re-capped tightly when not in use. Have a pice of
paper near by to get the ink flow even before tryin to mark
the PCB with the pen.
Sometimes you can buy rub-on transfers for tracks or pads
which you can incorporate as part of your pattern to make it
look neater. On the whole, however, this method is reserved
mostly for experimentation or very simple circuits with
broadly spaced tracks. Alternatively, you can also use
special tracking adhesives to paste out your tracks. Either
way, the end result is rather coarse and difficult to
Recently, there are available in the United States, special
transparencies which you can laser print or photostat your
track onto, and then iron-off the pattern from the
transparency onto the board. Below is an excerpt which says
something of this method:
There is a special transparency film called Tec
200 marketed for this purpose, but I've found that Avery
overhead transparency film works just as well, and is
available at most larger computer or office supply
stores. You just print your board layout to the
transparency with your CAD package laser driver, remember
you want a mirror image, and then iron it onto the
copper. The copper needs to be clean, just as it would be
for any resist application. You need a fairly hot clothes
iron to fuse the toner to the copper. I use a regular
home iron set for "cotton" and use an old Tee shirt
between the iron and the film. After it cools, you can
peel the transparency film off the circuit board and the
toner will remain behind as the resist pattern. There may
be a few pinholes or gaps where the toner didn't transfer
well. You can patch them up by hand with an ordinary
Note you can also use Avery film in ordinary copiers to
generate a transfer from magazine artwork or hand drawn
paper layouts. Of course when laser printing the film,
you need to adjust your CAD driver so that the laser
printer gives a properly dimensioned copy, and when using
a copier, one with infinitely adjustable "zoom" feature
is handy for the same purpose. If the artwork is
"normal", you can first make a copy to a transparency,
flip it over, and use that as your master for making the
Works good, costs little.
Another method I have come across of directly masking the
PCB is through the use of flatbed plotters. Apparently,
the ink used in these plotters are etch-resistant and if
you can design the board using CAD software, you should
be able to plot the mask directly onto the board using
the plotter. I have not tried this myself but a friend of
mine has and reports good success.
(Item by Gary Coffman)
Photo Resist Masking
This is probably the best way I know for making
nice looking PCBs. Unfortunately, the technology behind it
is rather obscure for many people entering the hobby and
remains a mystery for others. Thus I will try to demystify
the process here, with some luck. Contrary to the belief of
many, the photo-resist method does NOT produce tracks on the
PCB, it only produces a mask or pattern of etch-resist
material, after which the board still needs to be etched
like in all the other methods.
In this method, you need to get your pattern or mask onto a
piece of clear transparency. This is usually done by laser
printing direct on to the transparency, or photostating on
to it. This means that anything that can be photostated, eg.
patterns from magazines or from the ARRL handbook, or even
texts and pictures, can be etched. This adds a number of
advantages. For one, it is much easier to draw patterns on
normal paper than on the copper surface. There is no need to
use special etch resist ink for this purpose. You can also
draw lines with higher density and definition as well as
accuracy than you can using the direct method. You can use
PCB layout software to print out computer generated patterns
as well as including printed texts as part of the pattern.
The possibilities are numerous. It should be noted that all
the patterns must be black and white, no grays, and that the
transparency must be clear, clean and colorless.
Transparencies used for OHP presentations are suitable for
this purpose. As an additional hint, you should try to get
the transparency prepared such that the side with the toner
is also the side that will be in contact with the PCB during
exposure. This yields slightly better defined lines as there
is then only one clear edge. It does not matter that the
print is not completely opaque when you look at it against
the light, usually normal photostat contrast is sufficient.
You may want to cut the transparency to the size of the PCB
for easier handling. Do not scratch the transparency as the
toner may come off. If you notice missing tracks, you can
still fix it by drawing on the missing tracks using an
opaque black marker pen. If you notice excess tracks, slowly
scrape off the toner/ink gently using a paper cutting blade.
One advantage is that once you have produced one mask, you
can use the same mask to produce a number of identical
boards. When producing the mask, you should try to get it so
that the emulsion side (the print side) is the side that
contacts the PCB. This way when you expose the board, there
is a minimum of shadow and fringe effect at the edges of the
tracks and results in higher definition tracks.
The copper clad board must be specially prepared or
sensitized by spraying a film of photo-sensitive masking
material on to it. This spray is normally available in a
canister and leaves a coat of clear green color (usually)
when applied to the board. Spraying must be even and a
sufficiently thick film must be deposited and dried before
commencing exposure. All this should be done in low light/UV
conditions as the spray is photo-sensitive. Alternatively,
and more conveniently, boards that have been presensitized
can be purchased quite easily from the shops. In any case,
the spray is very expensive and not easy to use. These pre-
sensitized boards come in light-proof wrapping which you may
remove. The boards have a second protective plastic film
over the surface so you need not worry about accidentally
exposing the boards. The rate of reaction is way slower than
that of the camera film so you need not be overly concerned
of over exposure. Just be sure that you are not doing this
under intense fluorescent or sun- light. The second
protective layer is an opaque adhesive plastic layer which
is stuck to the board surface. This is usually white in
color. Do not peel off this layer until you are ready to
expose the board. If you do accidentally peel it off
pre-maturely, store the board in a dark place until you are
ready. In any case, these boards need to be stored in the
dark and in a cool environment.
Once your transparency is ready and you have cut the board
to size (without removing the protective layer), prepare
yourself a clear piece of flat glass such as that found in
picture frame. Be sure that the glass surface is clear and
clean, and that its size exceeds the size of the PCB. This
glass is used to hold the transparency to the PCB during
exposure. Put the PCB on a flat surface and align the
transparency over it, making sure that when you look at the
transparency, you see the exact image of the track/pattern
that you want, not the mirror image nor the
negative. Be sure your UV source is not active. Once
you are ready and have double-checked every detail, slowly
peel off the protective layer from the pre-sensitized PCB
and replace it on the flat surface. Under the protective
coating you should see a hard and dry, green film over the
copper. Place the transparency correctly over the PCB and
align it. Then, place the piece of glass over the
transparency to press it firmly to the PCB surface. Once
again check your alignment and then expose the board to the
The UV source can be a table top fluorescent lamp, or the
sun, or special UV lamps. In all cases the UV content is not
the same, thus exposure time varies. In my case, I use a
table top lamp with an 11-watt fluorescent tube and place it
about 2 to 3 inches above the board for 6 minutes to give me
a properly exposed board. Under the afternoon sun on a clear
day, it takes about 8 to 15 minutes to get sufficient
exposure. Under UV lamps, the period may be as short as 30
to 90 seconds depending on the intensity of your source.
Experimentation is the key to knowing how long to get the
right exposure. Excessive exposure will damage the board and
under-exposure will be equally disastrous. Once you have
determined the correct exposure time, however, it is the
same every time when using the same type of board, so be
prepared to experiment a little with your first few boards.
NEVER move or adjust the board once you have started
exposure. Once you get good at it, you can even expose a
number of boards simultaneously. Some types of board will
exhibit a slight color change on the exposed parts once they
are done but do not count of this method to determine when
to end because the change is barely perceptible. Note that
if you are using a UV lamp, be careful not to look at the
light direct as it may damage the eyes because the iris of
the eyes do not respond too well to UV and may result in
During the few minutes of exposure, get the developing
solution ready. This solution is normally sold in the same
shops where you purchased the PCB in the first place. They
sometimes come under the name of POSITIV 20 or something
similar and consists of an alkaline solution. Have this
ready when you finish exposing. If you observe the board
carefully, you may notice that the exposed portions are a
little lighter green in color than the masked portions. This
allows you to actually see a faint trace of your masking
pattern on the exposed board. Rinse the exposed board in the
developer solution and if properly exposed, you will see the
exposed parts of the green photo-sensitive film dissolve in
the developer solution. Once the unwanted parts have been
completed dissolved and washed away, rinse the board under
cold running water to remove any remaining developer
solution. You should now see a very clearly defined, green,
image of your original pattern on the PCB now. Dry the board
carefully, making sure that you do not accidentally scratch
off the resist/film. At this point you can still make
corrections to the pattern using etch-resist pens or by
scraping off resist/film from excess sections. Once
everything has been confirmed, put the board aside and
prepare for etching as outlined above.
Making your own PCB layout
There are a number of ways you can use to produce
your own photo-exposure masks and layouts. Typically you
want to draft out the layout on paper first before
committing it to the final mask. Be sure to take into
consideration RF paths and good grounding. There are a lot
of considerations that need to be taken into account of in
the design of a good PCB layout. Once you have drafted out
the layout you can use hand-drawn masks, or combine
hand-drawing with the use of Decal-Dry or rub-on transfers.
These methods are suitable only for low density/complexity
designs. The easiest way however is by the use of CAD
software. There are some easy to use but fairly competent
PCB CAD shareware available and if you intend to produce PCB
designs of your own, you should be familiar with such
software. Describing how they work is outside the scope of
this article but among the features of such software, are
their flexibility, multiple printer support, multiple layer
support, silk-screening support, automatic drill guides on
pads, auto-routing, easy editing, free/shareware, standard
component templates and the list goes on and on.
In summary, let me outline the steps and tools
involved in the direct PCB fabrication method.
First, the tools and
a) Ferric Chloride or Sodium Persulphate
crystals (or solution).
b) A plastic tray big enough to immerse the board
c) The single or double sided copper clad board.
d) Etch resist pen and/or transfers.
e) A small medium speed drill with 0.8 mm bits.
f) Hobby saw or Exacto knife to cut the PCB down to
g) File to give the board a good finish.
h) Mild abrasive for removing the resist from the PCB
The steps involved are as
a) Prepare a draft of the desired
b) Cut out the required size of the copper clad
c) File the edges of the cut down board for a smooth
d) Transfer the layout to the copper clad board by
drawing it on with the etch resist pen or transfers.
e) Double check for errors.
f) Prepare the etching solution as by adding 1 part
crystals to 4 or 5 parts water. Refer to section on
g) Immerse the masked board into the tray with the
h) Agitate the tray slightly for about 15 to 25
minutes, paying attention to the extent of the etch.
i) Remove board from tray when completely etched.
j) Rinse board under cold running water from the
k) Dilute used etching solution with lots of water
l) Use the mild abrasive to remove the etch-resist
from the board.
m) Use the drill to drill the appropriate holes for
n) Remove burrs from the holes.
For the photo-resist method,
the tools required are the following:
a) Ferric Chloride or Sodium Persulphate
crystals (or solution).
b) A plastic tray big enough to immerse the board
c) Pre-sensitized copper-clad board.
d) Transparency suitable for photostating.
e) UV light source. f) Developer solution.
g) A piece of clear glass to hold mask in place.
h) Marker pen or transfers.
i) A small medium speed drill with 0.8 mm bits.
j) Hobby saw or Exacto knife to cut the PCB down to
k) File to give the board a good finish.
l) Mild abrasive for removing the resist from the PCB
The steps involved in the
photo-resist method are as follows:
a) Prepare the masking pattern on a piece
of white paper.
b) Transfer pattern to the transparency by
c) Cut the pre-sensitized board down to size.
d) File the edges to remove unevenness.
e) Place transparency on the board to check
f) Peel of protective layer from board.
g) Align the transparency on the board.
h) Place glass over the transparency to hold it
firmly in place.
i) Place the UV source over the board and glass.
j) Activate the source and expose board for a
suitable period. Read above.
k) Rinse the exposed board with the developer
solution to dissolve unwanted resist.
l) Double check for errors.
m) Prepare the etching solution as by adding 1 part
crystals to 4 or 5 parts water. Refer to section on
n) Immerse the masked board into the tray with the
o) Agitate the tray slightly for about 15 to 25
minutes, paying attention to the extent of the etch.
p) Remove board from tray when completely etched.
q) Rinse board under cold running water from the
r) Dilute used etching solution with lots of water
s) Use the mild abrasive to remove the etch-resist
from the board.
t) Use the drill to drill the appropriate holes for
u) Remove burrs from the holes.
The real key to learning to make PCBs is to do it
yourself. In this article I have tried to provide a general
idea of the process of fabricating your own PCBs and have
purposely included a number of cautionary and warning notes
so that the reader will be aware of the hazards involved. On
the other hand I have been making my own PCBs for about 8
years now and have not suffered any side-effects or
Hopefully, this article will open new doors and
possibilities for the homebrewer and that through
homebrewing, one very significant aspect of the original
spirit of Amateur Radio may be restored. If there should be
further inquiries, I will be more than glad to help out.
Originally posted on the Low Power
Amateur Radio Discussion mailing list, December 7,