Making Homemade Single Side Printed Circuit Boards (PCBs) in your workshop can be very rewarding.

It is possible to make reliable homemade printed circuit boards at home. With the steps listed below you can get repeatable results every time. The techniques I am presenting have been tested and refined over numerous projects.

Instead of waiting weeks for custom boards to arrive from overseas manufacturers you can make your own board from start to finish in about an hour or so.

Required supplies:
Copper Clad Printed Circuit Board - PCB material
Phaser FX Toner Transfer Paper
Phaser FX Green TRF material
AVERY laser printable mailing label paper
Ferric Chloride
Plastic Etching Tray
Eye Protection
Plastic Nitrile Gloves
Small PCB Drill Bits
Fine-tip Sharpie marker
Temperature controlled soldering iron

Equipment Required:
Computer
Diptrace or similar PCB CAD package
Laser Printer or Plain Paper Laser Copier
Laminator
Drill Press

Nice to Have:
Microscope

1. Designing a single sided circuit board

I enjoy using the CAD program Diptrace to design my circuit boards because of its intuitive and easy to use GUI. Diptrace is made Novarm, Ltd.. Diptrace is available in a freeware version that works on up to 250 pins.

I find Diptrace is an easy to use Printed Circuit Board CAD design package. Diptrace has a schematic design module and a PCB design module. The two designs are tied together with a NETLIST that allows you to know the names of the pins and traces. The auto-router built into the PCB program can help you quickly route the traces in a circuit based upon the schematic design.

For making simple single sided PCB designs I recommend putting the through hole components, connectors, and any jumper wires on the top side of the board. Put the copper traces and surface mount components on the bottom side.

When using the auto-router set it to use 1 layer and start the auto-routing with the bottom layer active so the traces are made on the bottom layer.

As a design step for homemade PCBs I find it is easiest if I make the pads for through hole parts and VIAs 87 mil diameter and the center hole approx. 47 mil in size. This gives lots of copper to solder to and makes drilling easy. The last thing you want in the drilling process is to rip up tiny copper pads!

Don’t forget to put a power indicator LED on the board so you know the board is on. Also make sure that you have a current limiting resistor on any LEDs. Also don’t pull more than 25 millamps on any individual micro-controller pin.

A handy current limiting LED resistor calculator is:

http://home.cogeco.ca/~rpaisley4/LEDcalc.html

When using buttons don’t forget to add pull-down resistors or you may get strange results.

Also, it is a good idea to add polarized connectors to any power cords that are attached to the PCB.

It is also a good idea to use a DIP socket for DIP micro-controllers vs. soldering in the DIP chip directly during development and prototyping stages.

2. Printing off the design

Using a laser printer and toner transfer paper can allow you to get the circuit design out of the computer and onto the copper clad printed circuit board material.

To conserve materials I mark an arrow on the printing side of a piece of letter sized 8.5" x 11" paper showing the feed direction. Then I print off the design on the paper for positioning and alignment.

Next I cut out a small square of toner transfer paper that is 1 cm larger on all sides than the design. Make sure to place the toner transfer paper glossy side up.

Print off the design the with the following settings:

Print Resolution - 1200 DPI
Toner density - normal or Extra Dark Printing if available

In the Diptrace Print Window set the following settings:
Print the bottom layer non-mirrored at 100% scale.
Enable the printing of Pads, VIAs, holes, traces, connections, board, and assembly layers.
Disable the printing of Silk layers and tables.
Enable the Print in Black option so the board outline will be printed in Black.

I tape the small piece of toner transfer paper to the plain letter sized paper page using a strip of a sticky AVERY paper mailing label*.

*An important note is that if you use tape to hold down the toner transfer paper it will melt in the laser printer and jam the machine so use something like AVERY laser printable mailing label paper.

In my personal experience I have experimented with using glossy photo paper and magazine paper for doing toner transfer along with a clothing iron. The Pulsar FX Toner Transfer paper works very well with a laminator and provides the best results I have seen to date. If you use the real toner transfer paper it releases easily from the PCB when immersed in water. If you use glossy photo paper or magazine paper you will need to soak it for a long time and scrub it off with a tooth brush.

Just a reminder that you have to print off the design on a laser printer because it is the laser printer toner that provides the etching resist mask that will stop the traces from etching away. You cannot use an inkjet printer for this task. It is a good idea to use a laser printer that doesn’t leave behind any splotching or roller marks on the paper.

If you don’t have a laser printer you can take your design and print it off on plain paper with an inkjet printer and then use a laser photo copier to transfer the design onto the toner transfer paper. The laser copier will then transfer toner onto the toner transfer paper.

3. Cut the PCB material to size

Using a band saw cut the printed circuit board material to the size of your design. After you cut out the board, sand the edges to remove the roughness of the fiberglass.

Clean the new copper clad printed circuit board material. You may want to use very fine 320 grit sandpaper to prepare the board lightly so the toner transfers properly. After you sand the board, try to keep the oil from your fingers off the copper surface by holding the board by its edges.

4. Laminating Part 1

You will need to buy PCB material that is the right thickness for your laminator. Thin PCB material works well for most homemade PCB projects.

Let the laminator heat up fully. Using a cut strip from an Avery mailing label stick the toner transfer paper with the glossy printed side against the freshly cleaned copper side of the PCB material.

Set the laminator to its thickest mode.

Feed the PCB into the laminator a few times to guarantee that the toner is transferred from the paper onto the PCB material . I find between 5 to 7 passes through the laminator works well depending on the PCB board thickness.

Let the PCB board cool after laminating for a few minutes.

When the board is cool soak it in a container of luke-warm water for 3 minutes. This will soften the toner transfer paper. Once the PCB board and the toner transfer paper have been soaked the paper should slide right off the board without any force*. Pulsar FX toner transfer paper will release and leave behind no residue on the printed circuit board.

*Once again I will mention if you try and use any other paper besides toner transfer paper such as glossy magazine paper or glossy photo paper you will have to scrub off the paper backing with a tooth brush after soaking for a few minutes.

Dry the board with a clean piece of paper towel.

Hopefully the traces are a nice dark color and look solid.

5. Check your design against the actual PCB design

Gently set any surface mount components on the toner transferred PCB board to check for the proper pin 1 alignment of ICs and for proper scale and positioning.

What to do if you not happy with the design / toner transfer:
At this stage if you notice any problems with your PCB design you can remove the toner off the board using acetone. Acetone is an aggressive solvent so make sure to wear thick nitrile plastic gloves and safety glasses. Also, Acetone goes through latex gloves very quickly. In a well ventilated area transfer a small amount of acetone onto a folded piece of paper towel. Gently wipe the toner transfer off the printed circuit board.

Once the board is clean and dry you can revise the CAD design and repeat the printing and laminating steps.

6. Laminating Part 2

If most of the design looks perfect but there are any small breaks in the traces use a fine tip sharpie marker to fix them. This works well with Ferric Chloride etchant*.

*If you use Ammonia Per-sulfate etchant, sharpie markers won’t be able to fix problems in the toner transfer. The ammonia per-sulfate etchant will chew right through it. In this case cut thin pieces of electrical tape just large enough to fix the broken trace and apply it after you complete the green TRF laminating step.

Pulsar FX Green TRF material thickens the density of the toner transfer and can fill in areas that have a light toner transfer coating. The matte side of the toner transfer film goes against the printed circuit board.

Cut out a piece of green TRF film slightly larger than the PCB material. Leave a 1 cm longer section on the side that will be the leading edge on the toner transfer paper.

Fold the longer part over the edge of the board.

Feed the PCB and green TRF material into the laminator.

Once the laminator has a hold on the PCB provide a slight tension on the green TRF foil to keep it flat and wrinkle free.

Feed the green TRF film and PCB through the laminator 4 times for proper adhesion.

Let the PCB cool for about 2 minutes.

Peel off the green TRF foil. In areas where there is toner on the PCB the green TRF coating will stick. This will give the traces an almost plasticized appearance.

7. Etching Copper

Put on plastic gloves and eye protection.

Pour a small amount of Ferric Chloride into a shallow plastic sealable container. Label the container with the chemical name and write POISON on it. Keep it away from young children.

Place the toner transferred PCB into the etchant. Soak a disposable sponge in the ferric chloride and slowly rub the entire PCB material. Every so often dip the sponge in the etchant to suck up more. Rub the circuit board in a constant pattern for around two to three minutes until all of the unmasked copper has been etched away.

Once the unmasked copper has been etched away wash the board under water to stop the process.

Dry the PCB with paper towel.

Seal the container that you etched the board in.

Wipe the board with acetone to remove toner transfer resist mask.

8.Drill the PCB

Take your time when drilling and put on eye protection!!!

I find a 1.12 mm drill bit works well with my drill press. In my experience I find that if your drill press has any wobble in the chuck using the largest drill bit that will get the job done means the bits will last longer and are less likely to break.

Using a small drill bit drill out the pad and VIAs on PCB.

9. Soldering

Solder all of your surface mount components first.

I find it is best to put down the large surface mount ICs then work my way down to the smaller ones. Try and keep your time soldering surface mount components to the minimum so you don't over heat them.

Solder DIP parts, resistors, capacitors, next.

Then solder through hole connectors.

When soldering through hole components and especially DIP parts I find a bent conical tip works well. Also, I find it is best to put any jumper wires in last so they don’t get in the way of any other parts and you can make the wires as short as possible.

I solder most through hole components with a soldering iron temperature setting around 375°F.

As you are soldering the circuit board constantly clean your soldering iron tip on a wet sponge to remove dirt and residue that builds up.

If you have a microscope you will find it helps with inspecting the solder joints for quality assurance. I purchased a trinocular boom microscope off eBay and it has really helped with soldering tiny surface mount parts. The microscope I purchased has 6 inches of working height and I can use my soldering iron while looking through the stereo eyepieces. This allows you to easily solder pin to pin on a 64 pin TQFP.

Use solder wick to gently remove bridging between pins. Be careful when using solder wick that you don’t pull up any traces.

If you are using lead free solder solid-core SAC 305 solder be sure to add liquid flux when soldering.

I use a temperature controlled Ayoue solder station I bought off eBay. I am very satisfied with it.

9.Inspect the board

Use either a microscope or magnifying glass to inspect all of the traces for any problems. A digital camera set to macro mode can also be used to inspect the board.

10. Programming the Micro-Controllers

If you are using dip based micro-controllers, program them in your development board then install them into the PCB board. If you are using surface mount micro-controllers, you will need to use In-Circuit Serial Programming (ICSP) to program them.

For embedded projects I enjoy using MikroElektronica products for MCU development. Their EasyPIC boards and MikroC compilers are excellent.

One Response to “Making Homemade Single Side Printed Circuit Boards (PCBs)”

1. PCB Train says:

   December 6, 2011 at 11:55 am

   Very nice detailed tutorial and the photo of the finished product looks very good.