Introduction: Etch a Circuit Board With Kitchen Supplies
As you tinker with electronics projects, you'll quickly realize that the more complex they are, the more difficult they are to solder together. It usually means creating a rat's nest of individual wires, which can be bulky and hard to troubleshoot. Time to try making your own circuit boards at home! They're a great way to test new circuit designs, and make assembling your project a lot simpler later on—just add parts.
There's a catch, though: most of the existing kits out there use really nasty chemicals like ferric chloride or hydrochloric acid to etch the copper... so In this instructable, I'll show you a way to do it with stuff in your kitchen. Call it high-tech-low-tech circuit making, if you will..
- 1 copy of Autodesk Eagle (or another board design software)
- 1 package copper clad board (single-sided blank PCB)
- 1 package sticker paper (important: sure backing comes off in ONE BIG PIECE - no premade cuts)
- 1 clothes iron
- 1 office laser printer
- 1 bottle Acetone or nail polish
- 1 bottle of white vinegar
- 1 bottle hydrogen peroxide
- 1 box cooking salt (finely ground is best)
- 1 box Aluminum foil
- Gloves and eye protection
Step 1: Prepare Your PCB Design
Once you've tested your circuit on a breadboard, you can start to lay out your components in software. There are lots of ways to do it - I used Autodesk Eagle, which is free, but very powerful. I won't explain how to use it here—that's way outside the scope of one Instructable. If you want to learn, though, Sparkfun.com has some really great tutorials.
No matter what software you choose, you'll need to save or export the design as a PNG file in order to etch at home. (If you used Eagle, I wrote a quick how-to below).
When you're done, use image editing software like Gimp (or even iPhoto) to flip it and make a MIRROR IMAGE. If you don't, your final PCB will come out backwards.
Getting a board image out of Eagle:
- Click on the "layer settings" button. (looks like three multicolor squares).
- Make sure that ONLY the traces and pads on bottom of the board are displayed. This is the stuff that you want to physically see etched on your board. Usually this will be layer 16 ("Bottom"), 17 ("Pads"), 18 ("Vias"), and 20 ("Dimension)".
- Under the "file" menu, select "export", then "image".
- Set resolution to 1200 dpi, and BE SURE to select "monochrome."
- Give the file a name and save it.
Step 2: Prepare the Transfer Paper
Time to transfer your design to the copper PCB. To do this. you'll need to print it onto the sticker backing paper.
Why? By laser printing the design onto this non-stick paper, we'll be able to easily iron the toner onto the blank copper. Once it's stuck on, it forms a really nice mask—whatever copper is left exposed will be etched away; whatever is covered by printer toner will remain solid metal, forming your circuit.
First, prep the paper. Peel off all the stickers, and wipe the waxy side of the backing with some acetone. Be sure to let it dry. This will remove any oils from your fingers (or the stickers) and give you much more uniform results when you try print onto it.
Step 3: Print Your Transfer
Once the paper is ready, slide it into the "single sheet" tray of your laser printer (usually the one that folds down to accept things like envelopes). Make sure you're printing on the shiny, waxy side!!
If all goes well, you should have a print like the one shown above. If not, no worries - just wipe it off with acetone and try it again! You can usually get 2-3 uses out of a sheet before it starts getting too fragile to use.
Step 4: Transfer Design to PCB
Got a good print? Awesome. Now prep your blank copper board for the transfer.
- Wipe it with acetone and let it dry. DO NOT touch the surface again before the next step! Oil from your fingers will prevent the design from sticking to the copper.
- Attach the blank copper board face-up on a piece of cardboard or scrap wood. Some double-sided tape is helpful to keep it from moving.
- Lay your newly-printed PCB design over the copper board. You can tape the edges in place to keep the sheet from sliding around.
- Set an iron to high (Linen setting), and press down on the sticker paper covering the copper plate. Hold the iron in place, covering the whole board. NOTE: if your edges are coming out jagged or look runny, it means the toner is melting too much. Try putting the iron on a lower setting and just pressing for longer.
- Press hard for 60 seconds, then slowly move the iron while pressing for 3-4 minutes. I found it helpful to press gently on detailed areas with the tip of the iron to make sure they fully transfer.
- Remove heat and wait for board to cool a few minutes. While still warm (but not hot), gently peel off the transfer paper. If you did it right, your design will be stuck to the copper!
- Use a sharpie or nail polish to fill in any areas that didn't fully transfer, or came out faintly. If any traces are too close together, you can also scrape away some of the toner with an X-acto blade or needle.
Step 5: Etch Your Board!
The moment of truth. Put on your gloves and eye protection, and get ready to etch! Before you do though, a word of caution:
DO NOT, I repeat, DO NOT pour any acetone into the etching solution. Acetone and hydrogen peroxide can react to cause a highly flammable and possibly explosive chemical.Given the low concentrations of hydrogen peroxide we're using (3% solution), that's unlikely, you're still better safe than sorry. Now on with the show!
- Mix together a 1:1 ratio of vinegar and peroxide in a small tupperware container. I found it helpful to heat it in the microwave to speed up the chemical reaction.
- Add as much salt as the solution will hold.
- Lay the PCB with your newly-transferred design in the bin. You should hear a fizzing sound as the reaction starts to work.
- Occasionally stir the mixture, and add more salt and peroxide as needed. Some crud will form on the surface of the copper board as it dissolves - you can speed the process by wiping it off gently with a sponge or brush.
- After about an hour or so, your board should be done! Be sure to RINSE THE BOARD WITH WATER, then wipe the remaining toner off with acetone and let it dry.
- Next, drill holes in the component pads with tiny bits like these (a drill press or a steady hand helps - they break really easily).
You're almost ready to start soldering! The last thing to do (and this is important), is safely clean up your mess.
Step 6: Safely Dispose of the Etchant
When you're done etching, the liquid will look blue-green. That's because the process created copper (II) acetate, which is poisonous. It's not awesome to flush it down the drain, so we're going to neutralize it.
- Cut up about a square foot of aluminum foil into small pieces. Stir the pieces into the blue-green etch liquid, and leave outside for a few hours.
- The liquid will turn purple, and you'll see little brown specks settling to the bottom. Congrats: you just turned that copper chloride into harmless aluminum salts and elemental copper (the brown specks).
- Now you can dispose of it safely in your drain.
Final notes: Don't be discouraged if your board doesn't come out right the first time. It took a bit of trial and error to get mine the way I wanted them - but it's way faster and more satisfying than ordering boards from overseas!
Also: I am NOT a chemist - if you are, please weigh in on the disposal methods! For more info on this etching technique (and on disposal), there's a great discussion at Blondihacks.com. Happy building!
UPDATE: a few folks pointed out in the comments that my chemistry might be slightly off - with enough salt in the mix, the solution could turn green, meaning it's copper (II) chloride—the same stuff in some root killers. In that case, adding aluminum foil would just make another poisonous chemical, aluminum (II) chloride, and shouldn't be put down the drain. See discussion on stackexchange for more details.
if there's any doubt on whether or not it's safe to flush the liquid, though, you can always mix it with plaster of paris, wait for it to harden, and throw the whole thing away.
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3 years ago
Ferric chloride should be saved. It can be reused many times. When done don't dump it down a drain unless you know you don't have copper pipes and don't pour it into a stainless steel sink. It will or course etch either. Best just to pour it onto the ground where it will decompose into iron and chlorine. Iron is in many soils anyway. Red dirt is red because of the iron. And chlorine is already in most water supplies. If you're anal you might filter the copper out.
Reply 1 year ago
I have the same jar with the same solution of about 700 ml of water and ferric chloride, since I was a teenager in 1987. Sometimes I pass it through a paper filter. Sometimes I add more etchant. But the solution is always the same.
Question 1 year ago on Step 1
Do I HAVE to use a laser printer? I've got an inkjet and the budget won't go for anything else.
Answer 1 year ago
To use the heat transfer method, I'm afraid so... the reason the laser printer transfers its toner is because it's heat-activated. When the iron hits it, it effectively melts it off the sticker paper and onto the PCB copper. There are a few other methods online that will let you use an inkjet, but take a few more steps:
Reply 1 year ago
Thanks for the response. I'll have to come with another way.
Reply 1 year ago
No problem! If you do come up with another method, please post it here (or better yet, make an instructable!) I'm sure plenty of folks would be interested to know about it.
3 years ago on Step 6
Hello everyone, good intention but it might work it might not.
I regard to chemicals I will not comment, I did not experimented wit h this combination, but in regard to printing, paper used, transferring to copper PCB that is a whole new ballgame.
I can tell you from my own experience, it will not work, or at list not the way is expected.
I tried several methods, including this one, and none worked as described by people.
I run experiments for about three years and I finally found the right combination of steps to make it work, LIKE A CHARM, I might say.
here is the list of steps with material used:
paper; thin glossy PHOTO PAPER
PCB; normal, double or single sided, you can make double sided too
etchant; your choice, I used the old Ferric Chloride, as toxic as any other combination, as stated in this poster
TRANSFERING TO COPPER; OBSERVE UPPER CASE, YOU WILL NEED TWO ALUMINUM PLATES ABOUT 1/2" TO 3/4" THICK WITH AS PERFECT AS POSSIBLE SURFACE.
NEXT, SELECT THE TWO "PERFECT FLAT" SURFACE AND MAKE SURE THEY WILL FACE EACH OTHER WHEN YOU PUT THE COPPER PCB AND YOUR CIRCUIT DESIGN IN BETWEEN.
NOW, SET THE FIRST PLATE WITH FINE SURFSCE UP, LAY SOME REGULAR PRINTING PAPER ON IT, ABOUT 5 SHEETS, PLACE THE PCB AND YOUR PRINTED CIRCUIT ON TOP, OVER IT PUT ONE MORE LAYER OF PAPER ABOUT THE SAME AS FIRST.
SET THE SECOND ALUMINUM PLATE WIT THE FINE SURFACE ON TOP OF THEM ALL WITHOUT SLIDING, IT MIGHT GET MISALIGNED, IN TOP OF IT ALL PUT ABOUT 10Lb. WEIGHT, ALSO SLOWLY.
LAST STEP, SET IT ON TOP OF YOUR STOVE BURNER, THE BIG ONE, TURN IT ON AT ABOUT 2 - 3 FOR A SLOW HEATING AND FOLLOW THE TEMPERATURE TO BE AROUND 100 DEGREE CENTIGRADE ON THE BOTTOM PLATE, LET IT STAY FOR ABOUT 5 to 10 MINUTES, IT DOES DEPEND ON YOUR STOVE BURNER AND THE FLAME INTENSITY, YOU WILL HAVE TO RUN A FEW TESTS AND FIND OUT THE CORRECT ONE.
TURN OFF THE HEAT AND LET IT COOL AT ABOUT ROOM TEMPERATURE, REMOVE THE UPPER PLATE EASY, ALSO THE LAYER OF PAPER, NOT THE ARTWORK.
LASTLY REMOVE THE COPPER PCB WITH THE ARTWORK AND SPRAY IT WITH COLD WATER, LET IT SOAK FOR ABOUT AN HOUR OR SO AND START RUBBING THE PAPER WITH YOUR FINGERTIPS OR TOOTHBRUSH, USE SOME DETERGENT ON SOAKING WATER.
BY THE WAY, YOU CAN TRY WITH THE PAPER MENTIONED IN THIS ARTICLE, THE PROBLEM IS THE TONER WILL NOT STICK TO THE SHINY SURFACE EVENLY.
I know, it sounds like a whole world of trouble but believe me I made boards with 1/3 of a millimeter this traces, ALSO YOU CAN MAKE DOUBLE SIDED TOO.
I also used Win Qcad software with up to 1000 points, very easy to use and very complex file formats created by the software automatically that can be used to order outside to third party.
Have questions email me : m_hanczarek@hot mail.com
Reply 3 years ago
I have tried the same 2-3 years ago and it was totally successful but the problem was of holes how to drill holes, and by this technique you can make a single or two layer pcb nothing else
3 years ago
Interesting ideas ! I used these methods in the past, but I was never 100% satisfied with the results. I even used "special transfer paper" and many times I had to start all over... :(
So I used following method to make my PCB's :
- (Laser!)print the PCB drawing on transparent foil (use laser printer resistant and use "as black as possible"-setting on your printer)
- use PCB with photosensitive coating
Expose pcb with ultra violet light. I use an old (broken) flatbed scanner : remove everything out of it and glue some UV LED strips at the bottom and put in a small PSU.) In my case it takes about 70 seconds exposure time. Develop with natriumhydroxide until tracks are clearly visible (+/- 4-5 mins). Rinse with water and dry with kitchen paper. Then put the PCB in Natriumpersulphate to etch. With fresh-made acid, etching takes about 10 mins. I heat the acid in an old coffee-maker-can (glass!) to about 40°C. I hang the board (upside down) on a stiff wire in the acid and make it spin with a small motor (6V motor running on +/- 1V). When completely etched : rinse again and use acetone to remove the coating from the tracks, then dry. Coat the PCB with "solder-able lacquer" and let dry. This will preserve the copper traces and also makes it easier to drill holes.
Agree : this is not done with 'kitchen" materials, but the result is SUPER ! I managed to make PCB's with TWO tracks between 2 adjacent legs of an IC ! and the total time to make a (small) PCB takes about 30-40 mins ...
The cost of all the chemicals is about 20€/$ but you make quite a lot PCB's with it.
The cost of photo sensitive PCB is just a little higher than "naked" boards, but success is almost 100% !
Another tip : don't use "epoxy" PCB (unless you really need super strong and sturdy PCB's) : it will save you a lot of money on drill bits ... After drilling about 100 holes (0.8mm), your bit will be dull and unusable. On laminated paper FR2 boards you'll drill a few 1000's with the same bit!
Contact me if you need more info ! (44meurope at gmail dot com)
PS : I buy my products at www.reichelt.com
3 years ago
I've used transfer paper to make boards myself for years when I need them (although I still use ferric chloride to etch).
A couple of things to make the process better:
- Before transferring the image onto the board give it a clean with steel wool and an abrasive cleaner (like ajax) to shine it up. Dry it and then use a non stick cleaner (like your acetone, mentholated spirits or grease and wax remover)
- Put the iron on the board for a few seconds to preheat it, then lay the transfer on the board with the iron on top to heat the whole thing. The transfer will stick better
- Once the board is etched and clean, spray a coat of lacquer over to protect the tracks from corroding (you can generally buy a can of it at the local electronics store) and will last you for years.
Reply 3 years ago
I'm trying to make my first home made pcb, thanks for the tips.
3 years ago
Good work - The sticker paper is a brilliant idea!
I have used this stuff before and I have found it better because the etchant is re-usable and works relatively fast.
I have not etched a board in many years now though (mostly use CNC track isolation for making boards). Also, an alternative to the Iron is to use a laminator. You just have to find the right type that applies the heat in the roller (like a laser printer) rather than heat, then roller. These are easy to identify as they are generally taller. For me, that was a blue 'GBC Creative A4' laminator that I modded a tad to up the temp. Consistent, easy results.
Also, as someone else suggested, cleaning the board with some sort of abrasive is good but I always avoided steel wool (it made soldering harder after as it has a galvanic reaction with the copper), I used green plastic scourer/brillo and it worked very well.
Tip 3 years ago
vinegar can be supstituted with citric acid. To me it's more safe
3 years ago
Nice writeup!. I always mess up the transfer and you gave good tips here. My only nitpick is the title, because I came here thinking "oh nice, there's a way to avoid hydrogen peroxide and ferric chloride!" which are things I can't find in my kitchen.
Tip 3 years ago
Thank you for this - I never tried hydrogen Peroxide before (I’m usually a Ferric Chloride man...) but may I make one suggestion? After you’ve done the ironing, carefully inspect the traces & use an etch pen (we knew it as a Dalo pen) to fill in any little bits which didn’t quite adhere. Thanx again, 6A8G.
3 years ago
I used this technique quit a bit back in the day of through hole parts.
i found it extremely difficult to drill the holes without breaking many, many very brittle drill bits.
I found that putting the board (after applying toner and removing paper) in a toaster oven worked wonders.
Heat or “toast” the board face up until you see the toner just begins to melt.
It will gloss up a bit.
(I used to know the exact temperature to set the toaster oven, but forgot long ago).
It ends up looking like the “raised ink” on business cards.
This extra princess step seems to significantly reduce pinholes in the toner that lead to bad traces.
i think it also helps seal the toner to the board so you get less lifting and undercutting.
3 years ago on Introduction
Nicely done. When you say "1 bottle Acetone or nail polish", shouldn't it be "1 bottle Acetone or nail polish remover" ?
3 years ago
A few years ago I wanted to experiment with 'super (ultra?) capacitors to make a rechargeable 16v power bank. If circuit isn't too complicated you can use a Sharpie and just draw it directly onto copper clad board.. May need to make lines a little wider and go over them a couple of times but it actually works well and doesn't require access to a lazer printer. AS far as I recall I used same set of chemicals, although I can't remember if I added table salt? I do remember that the solution became so saturated with copper that any metal dipped in it became coated with a copper powder after a very short time.
3 years ago
If you try to etch a pc board be patient. You are not likely to get great results on the first tries. It's not easy and there are many ways to make a mistake. Or not make a mistake and just don't do a great job. Great results can be had by amateurs, but it's not easy. Full filling perhaps, but not easy.
3 years ago on Step 6
Ferric chloride is probably safer than the hydrogen peroxide and acetone solution. But none of them is much of a problem for the person making a few boards a year. In an industrial situation, the effects of almost any chemical need to be mitigated before dumping them back into our environment. Not because the chemicals are dangerous, but because they may overwhelm the water or grounds ability to decompose them. Or they decompose into dangerous chemicals. Nothing dangerous about the components of Ferric Chloride (iron and chlorine), hydrogen peroxide(hydrogen and oxygen), or acetone(carbon, hydrogen and oxygen). People have reached the point where if they don't mention disposal in an instructable someone will get on a box and proclaim them ignorant and a destroyer of the earth. Even if there is no problem. It makes them feel good.