GBPPR Homebrew Printed Circuit Boards

Overview

This is an article on how to make Printed Circuit Boards (PCB) for electronics project without the need for spending alot of money on expensive transparencies, toner, or by having the board make commercially.

This process may seem complicated at first, and you'll want to study and practice on scrap board material before hand, but it has turned out to work quite well.

No fancy equipment (or software) is required as the PC board pattern will be laid out by hand using hobby store markers and a straight edge.  With a little practice, you can make a small PC board in under an hour.

You'll sometimes find scraps of high-quality PC board material at ham radio swapfests for very low cost, but they may be tarnished or dirty from being outside.

Don't let this stop you from purchasing the PC board material, as it's easily cleaned up using common household chemicals and a little elbow grease.

Pictures & Construction Notes

Use a Midwest M1200 3.5-inch snips to cut the PC board to the size you require.  These are very nice snips which cost only around $30.  Harbor Freight Tools makes a knock-off for $10, but the final cut will not be as precise.

Then use Copper Glo and a non-metallic 3M scrub pad to remove any copper oxidation or dirt.  Scrub the PC board in a circular pattern after dipping the 3M pad in water.  Repeat this process four or five times to each side of the board.

Let the PC board dry under an incandescent lamp or on a hot plate.

Shown above are some of the markers used for the laying out the etch resist pattern.  The main layout is done using a Sakura IDenti-Pen which has a dual tip for fine and extra fine lines.  These Sakura pens are available at Michaels hobby stores.

For filling in the larger areas, regular Sharpie markers with the wider tips are used.

Keep multiple IDenti-Pens around and rotate through them as you do the layout.  This will keep the tips from drying out.

Straight edges are Staedtler rulers from the hobby store.

Frequently clean the straight edge with denatured alcohol and a paper towel to prevent marker residue from building up and "smearing" onto the PC board pattern.

You can also use drafting tape or plastic model pin stripping material from the hobby store to make much more "professional" looking traces.

You may wish to do the circuit layout on paper first to get a general idea of where everything should go.

Then using an IDenti-Pen and straight edge, layout the circuit traces as required.  Remember that you are laying down an etch resist and anything covered in marker will NOT be etched away.

Use an X-acto knife or razor blade to scrap away the marker trace when you need open areas or to correct any mistakes.

Completed layout in marker.

Anything covered in black marker will not be etched away.

To check the spacing of the traces, keep some spare components around and set them on top of the traces.

Mask off some of the larger areas not to be etched and the bottom of the board, if required, using masking tape.

You now want to let the marker ink dry under an incandescent lamp or on a hot plate.

Next is the etching process.

Etch the board in a solution of heated ferric chloride, which is still available at Radio Shack.

The etching tank shown above is/was available from Circuit Specialists.

Finished etched PC board.

Clean the remaining etch resist off using denatured alcohol and a non-metallic 3M scrub pad.

Scrub again with Copper Glo and let the board dry under an incandescent lamp or on a hot plate.

Now it's time to drill the holes for the ground vias.  These connect the top and bottom ground planes of the PC board using low-inductance pieces of wires.

Any circuit operating at frequencies higher than audio will require closer spaced ground vias.  These vias are also handy for heat dissipation.

To drill the ground via holes, use a 0.22-inch drill bit in a Dremel tool with a drill bit chuck.  I keep a Dremel set aside specifically for this drilling purpose to avoid any unwanted "side" wear on the Dremel's bearings.

You'll also want to drill (and file) any other larger holes which may be required.

Scrub the drilled PC board again with Copper Glo and let the board dry under an incandescent lamp or on a hot plate.

Next is tin plating the PC board, which is optional.  This will prevent any exposed copper from oxidizing.

Be sure not to touch the PC board with your bare hands at this point and double check that the board is clean of any dust or debris.

Tin the board using MG Chemicals Liquid Tin placed in a glass pan.  Let the PC board soak in the tinning solution for at least five minutes.

Lightly scrub the PC board with a non-metallic brush to coat any places on the tinning solution has trouble on or missed.

Be sure to keep any utensils used for tinning and etching separate!

Finished drilled and tinned PC board.

Rinse the PC board with clean water to remove any remaining tinning solution and then let the board dry under an incandescent lamp or on a hot plate.

Don't scrub the PC board with an abrasive pad from this point on or you'll rub the tin plating off.

You may wish to "buff" the PC board with a paper towel and a bit of denatured alcohol to prepare it for soldering.

Now it's time to install the ground vias.

The vias will be made using #24 gauge solid tinned-copper bus wire which is available from Radio Shack (278-1341).

You'll want to use high-quality wire cutters to trim the bus wire.  The Xuron Xuro-Shear 2175 is shown above and is available at most hobby stores.  The Xuron cutters have a little heavier-duty blade than the Xcelite brand cutters.

Cut off a short length of the #24 bus wire at place it through the ground via holes.

Solder the wire only on the top side of the board at this time.  Leave at least a 1/4-inch of the wire sticking up.

Finished installing all the ground via wires.

Solder is only on top side at this point.

Now flip the PC board over and start soldering the via wires on the bottom of the board.

Finished soldering all the ground via wires on the bottom of the PC board.

Using the wire cutters, trim the ground via wires down at much as possible only on the bottom of the PC board.

Next is an optional step, but is highly recommended.

Using the side of the soldering iron's tip, push down the remaining "nub" of the ground via wires so they are flush to the bottom of the PC board.

You'll also want to "pool" the solder so the area around the ground via is fairly flat.

This will all take a lot of practice, but the finished boards look really nice.

Finished bottom of the PC board.

Clean off any excess solder rosin with denatured alcohol and a non-lint cloth.

Now trim the ground via wires on the top side of the PC board.

Clean off any excess solder rosin with denatured alcohol and a non-lint cloth.

To keep the PC board clean while you are installing components, use a cotton swab or trimmed-down flux brush dipped in denatured alcohol to clean around each component as you solder them onto the PC board.