HOWTO: Create your own PCBs on the cheap!

[GooSE]

Creating your own printed circuit boards (PCBs) using toner transfers can be done cheaply and easily by almost anyone, providing that you are patient and possess some common tools and equipment. This guide will describe and show how this process works. For this example I will be creating a PCB for FENG3’s Multi PIC Programmer 5V2 (alternate version), which can be found here: http://feng3.cool.ne.jp/en/pg5v2.html

NOTE: This process involves working with dangerous chemicals and tools, and you must take due care if following these instructions. Neither I nor Overclockers Australia will be held liable for any damage to yourself or your property in the event of an accident.

Required equipment & materials:
- A sheet of bare copper-clad PCB
- Glossy photo paper
- A laser printer
- A saw of some sort for cutting your PCBs
- A clothes iron
- A drill/dremel with suitably sized drill bits
- Acetone
- Hydrochloric acid
- Hydrogen peroxide
- Demineralised water
- A plastic container
- Abrasive pad or sandpaper

Firstly you will have to measure & cut your board to size. I measured mine with a ruler and marked it out with a permanent marker. What type of saw you use to cut your board is up to you – I used a hacksaw and the cut didn’t turn out very bad at all. I recommend deburring with a file.

Next you will need to ready your PCB artwork for transfer onto the board. This is done by printing out your artwork onto glossy photo paper using a laser printer and then ironing the pattern onto the board. For this step I used a HP LaserJet 2200 and some OfficeOne photo paper from OfficeWorks. I have also had success with Kyocera Mita and Samsung laser printers as well as Oki LED printers. Make sure you have the resolution on the maximum setting (600dpi for me), and turn off any sort of toner saving features. On the HP printer I had to adjust a setting called ‘toner density’ to the maximum.

To prepare the board for the toner transfer you should probably give it a rub down with a synthetic abrasive pad (a.k.a. scotch pad) or some fine-grit sandpaper (I had some 1200 grit wet & dry which I used) and then clean it all up with acetone. You should now be left with something like this (excuse the bluriness, I forgot to enable macro mode):


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Now you’re ready for ironing. Turn off any sort of steam settings and adjust the temperature to the maximum (this setting was called ‘linen’ on my iron). Let the iron heat up and place your paper face-down onto the copper side of the board. To set the paper in place on the board simply iron a corner for a few seconds and it should stick. To iron the design on I let the iron sit on the paper/board for about 2-3 minutes to heat everything up and then push down as hard as I can on the iron for about 30 seconds. After this you may want to work the iron over the board to make sure no areas were missed.

After the board has cooled down place it in some hot, soapy water and let it soak for about 15 minutes. After it has soaked you should be able to start rubbing the paper off with your thumbs. DO NOT peel it like a sticker as this may lift the toner also! The friction from my fingers was able to remove all the paper quite easily – rub as hard as you want as the toner will not rub off easily without a solvent. When all the paper is gone rinse your board in some clean water and dry it.

If the pattern didn’t transfer properly you can clean the design off with acetone and try again. You may want to try different paper or a different printer. If the pattern transfer was successful you should be left with something like this:


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You can use a permanent marker to fill in any small spots which didn’t transfer properly. I tried both Artline and Sharpie markers and found the Sharpie to be superior.

The etching solution I prefer (hydrochloric acid + hydrogen peroxide) is both cheaper and as fast as, if not faster than, the two most common etchants (ammonium persulfate and ferric chloride). The actual etchant is the acid, while the peroxide is used to replenish the acid which is used up in its reaction with copper. I use a 1:1 mixture of 15% hydrochloric acid and 3% hydrogen peroxide.

Hydrochloric acid (a.k.a. muriatic acid) is usually sold in hardware stores with a concentration of 30% while hydrogen peroxide is usually sold at chemists as an antiseptic with a concentration of 6%. Obviously this must be diluted, therefore the correct ratio for the etching solution is 1:1:2 of acid, peroxide and demineralised water, respectively.

CAUTION: Make sure to add the peroxide/water to the acid, not the other way around. If you add the acid to the peroxide and/or water the acid may boil instantly and scald you. If you get acid on yourself you should wash it IMMEDIATELY under running water. Also, the mixing/etching should be done in a well ventilated area and you should dispose of the used chemicals thoughtfully.

NOTE: I also highly recommend wearing nitrile gloves (latex gloves will not protect you from the acid) and safety glasses.

Mix your etching solution in a plastic container (don’t be alarmed if the solution turns brown when you add the peroxide) and simply place your board in. To speed up the process you may want to agitate the solution by stirring it with some kind of plastic instrument (I use a plastic spoon). The process should only take about 10 minutes, but obviously this depends on how much solution you use and how much copper needs to be etched. Here is a shot of my board about half way through the etching process; notice that the reaction starts at the outside and works its way in:


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Once the etching is complete remove your board and rinse it under clean water, dry it, and then clean the toner off the board using acetone. You should be left with this:


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Drilling the board, in my opinion, is the trickiest part. Unfortunately I don’t have a drill press, so I use a dremel-type rotary tool to drill my boards. You will be working with small drill bits (probably 0.8mm or 1.0mm) so you will need a small collet (for dremels) or chuck (for conventional electric drills or presses). In my case I used a 0.8mm drill bit with a 1/32” collet – if you use a drill you will probably need something called a finger chuck. If you want to make it hard for yourself you can get a tool called a pin vice and do every hole by hand, but I don’t recommend it.

NOTE: I highly recommend wearing safety glasses while drilling.

Some people recommend centre punching each hole before drilling but I didn’t really notice a difference when I tried it. Just go slowly and be patient. This is my finished product:


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Notice that the large copper section on the left is heavily tarnished – I assume that this could have been eliminated by used a PCB lacquer immediately after etching. Also, I know I screwed up the two big holes on the right and a few small ones, but they don’t really matter.

So there you have it, a board ready for soldering that only cost a few bucks to create. The chemicals are the most expensive part, but you should get a few boards out of each batch. I hope some of you guys and girls find this guide useful. If there are any questions or comments, don’t hesitate to hit reply.

Cheers.

[SnooP-WiggleS]

Nice guide vote for sticky

[-KoMoD0-]

nice

ditto about the sticky, also add it to the wiki

[dephilile]

Where did you get the sheet of bare copper-clad PCB from?

Also, what is the narrowest track you can successfully do using this process?

[GooSE]

I got this sheet from Jaycar (in 150mm x 150mm form), but any half decent supplier will stock them.

I've heard that this process works down to track sizes of about 10 thou, which is about 0.25mm. Not bad...

[Rass]

You can buy D.I.Y kits from dick smith electronics for about $20 from memory. It contains some of the acid, a couple of boards and an etching pen along with instructions.

[nux]

Originally Posted by dephilile

Also, what is the narrowest track you can successfully do using this process?

I've made a few this way and can get traces reliably to about 0.5mm, possibly even thinner.

[Goth]

Originally Posted by Rass

You can buy D.I.Y kits from dick smith electronics for about $20 from memory. It contains some of the acid, a couple of boards and an etching pen along with instructions.

But the draw-with-a-marker method is an absolute joke, anything that you can make a board for successfully by that means isn't worth fabricating a board for, anyway.

Nice guide. Perhaps sticky or something?

By the way, don't allow Acetone or anything else to come in contact with the etching chemicals.

[nux]

Originally Posted by Goth

But the draw-with-a-marker method is an absolute joke, anything that you can make a board for successfully by that means isn't worth fabricating a board for, anyway.

Actually, the kit he's talking about contains an etch resistant pen. They're quite useful to touch up transfers that haven't gone perfectly. The old laser printer I use tends to leave a few gaps. I find a permanent marker works good as well.

[Goth]

Originally Posted by nuxie1

Actually, the kit he's talking about contains an etch resistant pen. They're quite useful to touch up transfers that haven't gone perfectly. The old laser printer I use tends to leave a few gaps. I find a permanent marker works good as well.

Yeah, I know.

But what i'm saying is that drawing up a board from scratch with a pen/marker is pretty much useless.

[dephilile]

Originally Posted by GooSE

I've heard that this process works down to track sizes of about 10 thou, which is about 0.25mm. Not bad...

damn, that's really good. i'm guessing you need to get a really good transfer to the PCB from the paper. Are you talking about professionally made PCB’s or ones using this process (i.e. ironing the tracks onto the PCB)?

[nux]

Originally Posted by dephilile

damn, that's really good. i'm guessing you need to get a really good transfer to the PCB from the paper. Are you talking about professionally made PCB’s or ones using this process (i.e. ironing the tracks onto the PCB)?

Toner transfer method, and it doesn't need to be a great transfer either.
Here is a board I made a few weeks ago with a 28 pin SOIC chip. Each pin is less than 1.27mm apart and 0.42mm wide. As you can see, most of the gaps between the traces and ground plane are less than half that width.

[dephilile]

Originally Posted by nuxie1

Toner transfer method, and it doesn't need to be a great transfer either.
Here is a board I made a few weeks ago with a 28 pin SOIC chip. Each pin is less than 1.27mm apart and 0.42mm wide. As you can see, most of the gaps between the traces and ground plane are less than half that width.

wow, that turned out really good. i was just wondering how well it would work for surface mount IC's.

[Z3PHER]

Originally Posted by dephilile

wow, that turned out really good. i was just wondering how well it would work for surface mount IC's.

I'm guessing it'd depend on how well you did it. we did this stuff at school and it ended up dodgy as . But i'm sure with practice it'd get better.

P.S I think i know you

[imgod22222]

I'm sorry, this is a pretty darn noob question, but exactly what is it called to be able to make a layout for the PCB? I'm in high school ATM and I want to take classes in college to learn how to make my own circuit boards/microcontrollers. What would the "subject" be called? (the OP says "PCB artwork") To understand how to do that... what would it be called?