As an electronics hobbyist, I need sometimes to create custom PCBs. You have a lot of different methods available for an amateur : engraving with a CNC router, etching with perchlorate, toner-transfer method...
I usually use the transfer-toner method for my PCBs. But today, a little piece of copper was here on my desk, and I was looking for a method to create quickly a PCB.
I used a special pen for this. I was able to fully create this small PCB in less than 45 minutes (no drilling yet) ! And besides, it doesn't require special hardware ! You should have everything at home.
Follow these simple steps !
This Instructable assumes that you have a good level in electronics. Watch out, this Instructable involves PCB making, with chemical and dangerous products. Always wear protective glasses/gloves and wear a safety clothes !
Once finished, recycle the etching solution.
Step 1: Select a Schematics
Ok, I love making guitar effects pedals. I was looking for a simple design, something with one transistor.
After a few seconds of google, I discovered this forum page and the design of the "5th gear overdrive". It's a very simple design, with one Darlington transistor.
I thank the author of this circuit for sharing his work on the net !
My method will not work on very hard designs (you may try...), and if the design involves ICs in DIP cases. You will understand in the next step why.
Step 2: The Design
Ok, you will need :
- copper plate
- sheet of paper for drafts designs,
- a pencil
I usually lightly scratch the copper side of the plate with fine sandpaper, and degrease it with alcohol.
Start by drawing the edges of the copper plate on the paper. Then, following the schematics, create the signal tracks, by hand. For this pedal, I created the ground line on the bottom, the input on the left and the output on the right.
Remember that you will draw on the copper side, so watch out for parts orientation ! I checked the transistor pinout, the base is the middle pin. I used my experience for the parts size (about 12 mm for the resistors, less for capacitors)
If your circuit involves a DIP integrated circuit or similar, you must take care of the orientation, and on the pads location ! As I draw by hand, it's hard to create something nice. For a drawing like this one (with a transistor) it's not a problem. If the drawing is hard, it's better not to use this method, but a classical toner-transfer method or similar.
As soon as the drawing looks good on the paper, redraw it on the copper plate. Create small circles for components pads. You should be able to erase a wrong line with your finger.
Step 3: The Secret Weapon
Ok, the idea for etching is to protect the copper tracks with a suitable material (toner, for example). But here, to protect the copper, we will use a device that every kid should have in these pencil case : a correction pen.
It's a great idea, as this white paint will be strong enough to protect the copper and to resist the the etching solution. It's cheap, and you can draw thin lines, of about one millimeter.
Clean the tip with a cloth, and shake the pen. Check on a paper if it works correctly. Try to create continuous lines. On my pen, you need to push it down and lightly squeeze it. Once you can draw beautiful lines, draw "correction" lines over the pencil lines on the PCB. If you have space, just draw something freestyle ! You can write text, draw things... Just be creative ! Ok, on my small copper plate, it was hard to put the name of the effect and my nickname... :-)
When everything is all-right, just let it dry.
Step 4: Etching !
Ok, I didn't have my bottle of perchlorate with me, so I used a mix water-acid-peroxide water (1/3 1/3 1/3).
I use clear tape to create an "handle" to move the circuit into the etching solution. I use disposable plates for this.
After 10 minutes, here is the result. The copper is gone !
Use nail polisher to remove the white "paint". Here you are ! You just have to drill the holes and turn on the soldering iron !
This method is great to quickly create simple designs, like this one. For more hard designs, I suggest a more accurate method, like the toner-transfer.
Thanks for reading !