Introduction: PCB Etching (prototyping)

Making circuits is great but what if you want to make your ideas a bit more permanent? That´s when it´s great to be able to make your own PCBs at home.

I´ll show you how to make your own single sided Printed Circuit Boards at home. If you want to get one step further you can also learn how to tin and apply a solder-resist dryfilm to it.

Step 1: Things You Need.

Chemicals:

  • Sodiumpersulfate - Na2S2O8
  • Sodium Carbonate aka. washing soda - Na2CO3 (Optional only for dry film)
  • Distilled water
  • Fotopositive developer - NaOH

Materials:

  • Foto coated PCB
  • Printer film

Tools:

  • Rotary tool
  • Jigsaw (only if you plan to cut out something on your pcb)
  • Nibbler (can be handy)
  • Plastic tweezers
  • Something for sanding
  • Brush
  • Exposure unit with frame* (UV lamp)
  • Etching unit (or beaker and heatplate)

Others:

  • Gloves
  • Open container for developing
  • Eye protection
  • Funnel (for filling liquids back into their bottles)

Optional:

  • Dry film solder stop laminate
  • Laminator
  • Chemical tinning fluid

*I´ll show you later on

Step 2: Create and Print Your Layout.

1. Use your favourite Cad Software (mine is Cadsoft eagle) to design a PCB layout.

2. Open the layer settings and only enable the copper (top or bottom, depending on what type of pcb you´re planning to make), the pads, the Vias and the dimension layers.

3. Put some printable transparency films into your printer.

4. Press the print button in your cad software and print out a black, real-scale version of your layout. Depending on your printer you may have to print the layout twice and then stick the two printed films on top of each other to get a fully light stopping image.

If you want to add a solder resist later on:

1. Get back to your Cad software and open the layers menu

2. Now only enable the top-stop layer (or the bottom-stop layer, again depending on the type of pcb you´re planning to make)

3. Repeat the point 4.

Step 3: Expose the PCB

1. Peel off the protective layer from your PCB. Make sure you don´t touch the copper side of the PCB after removing the protective layer because if you do you´ll have problems developing it

2. Align the printed film and the PCB so that all of the traces on the film have copper underneath them.

3. Put the PCB and the already aligned film betwen two glass plates to keep the film flat on the surface of the PCB. Use some magnets to hold the glass plates together (like shown in the pictures)

4. Now expose the PCB to UV light. I used a 25W party UV light and it took about 5 minutes to finish exposing

Step 4: Developing the PCB

Now it´s time to put on your gloves and eye protection.Don't take them off during the entire etching process


1. Mix the developer following the description on its package. I´ve never tried it myself but 10g of NaOH in 1 litre of water should work as well.

2. Put your PCB into the developer solution immediately after finishing the process of exposing.

3. Use your brush to help the developer remove the photoresist.

4. Do this for about 30 seconds until no photoresist is coming off anymore but don´t take it out yet. Let it develop a little bit longer than it seems to need. That way you can be sure that all of the unnecessary photoresist is removed. Otherwise your etching results will ruin your day.

5. Rinse the PCB with tap water and move on to the next step

NOTES:

  • When you have finished developing take your developer and pour it into your sink. It´s basically the same stuff used for drain cleaners.

Step 5: Etching

1. Mix your etchant: Use 250g of sodiumpersulfate (Na2S2O8) per litre of distilled water.

2. Pour the etchant into your etching unit and heat it to 50 °C (don´t overheat it because sodiumpersulfate starts to decompose at over 50°C)

If you don´t have an etching unit just fill the etchant into a heat resistant beaker and put it on top of a heatplate. Also heat it up to about 50°C

3. As soon as the etchant has reached its final temerature take your PCB, put it inside and start the air supply of your etching unit (If you use the beaker method take a stirring rod and just stir the solution with the PCB in it.)

4. Leave it inside the etchant until all of the copper has "disappeared"

5. Rinse the PCB with tap water.

6. If you use an etching unit make sure you take out the etchant and store it in another not airtight container. Otherwise your air bubbler may get damaged.

NOTES:

  • The etchant will turn blue and start getting inefficient after a couple of PCBs. When you realise that the etching process starts taking way longer, change your etchant and take the old one to your local chemical waste center Warning: "The used etching solution contains dissolved copper which isn´t good for your environment "

Step 6: Tinning (optional)

1. Remove the excess photoresist by cleaning the PCB with acetone

2. Take your tinning fluid and fill it into an open container.

3. Put your PCB into it and leave it in there for about 5 - 10 minutes

4. Take the PCB out of the solution and rinse it with tap water

5. Pour the tinning fluid back into a glass bottle using the funnel. Store it in a place where no pets or kids can reach it.

NOTES:

The tinning fluid is reusable, but after some time the efficiency will decrease. If this is the case bring it to your local chemical waste center.

Step 7: Drilling

1. Take the rotary tool and the right sized drill bit.

2. If you have a drill stand, fix your rotary tool in it.

3. Make sure you´ve got good light so that you can clearly see where the holes need to be.

4. Drill all the holes you need

5. Clean your pcb.


Step 8: Photoresist (the Next Few Steps Are Optional)

Before you start, turn on your laminator so you don´t have to wait for it at point 6.

1. Get some Solder resist dry-film

2. Then dim the lights and take it out of its lightproof packaging

3. Take two pieces of strong tape and stick them to the top and the bottom side of one corner.

4. Then pull the two pieces of tape apart like shown in the pictures. You´ll end up with one transparent and one green layer. Put the transparent layer to the trash and hold on to the green one.

5. The green layer has got two sides, one side is mat and the other side is shiny. Take your PCB and lay the mat side of the dryfilm onto it. Make sure you don´t get any bubbles in between them.

6. Once your laminator has reached its final temperature (which should be about 150 °C), put your PCB onto a piece of paper and run it through the laminator 2 - 5 times. Just make sure that the entire PCB gets hot.

Step 9: Exopse the Laminate

1. Take the film for the solder mask you printed in step 2 and align it with your PCB.

2. Again clamp the PCB and film between two glass plates using some strong magnets.

3. Expose the PCB to UV light (It takes about 6 minutes with my 25W UV lamp).

4. Now you have to let the PCB rest in a dark place for about 1 hour.


Note: All the areas that don´t get exposed to the UV light will come off in the development process.


Step 10: Developing the Dryfilm

1. Mix the developer by dissolving 10 g of sodium carbonate into one litre of water (You won´t need the whole litre. I just used 100 ml of it)

2. Remove the last transparent protective layer with the help of some adhesive tape (like shown in the pictures)

3. Put your PCB into the developer solution and use a brush to help the developer remove the solder resist from all of the pads.

4. When all of the unnecessary dryfilm has been removed take the PCB out of the solution and rinse it with tap water.

Step 11: Hardening the Dryfilm

1. Take your PCB and harden the dry film by exposing it to UV light. With my 25 W uv lamp it takes about one hour (I expose it for 1/2 hour then I let it cool off and after that I expose it for another 1/2 hour)

2. You can make sure that it has finished hardening by trying to scratch the dryfilm with your fingernail, you shouldn´t be able to scratch it after hardening.

Step 12: Cut Out Your PCB

If you´ve done it like me you will now have to cut out your tiny boards, if not you´ll just need to cut the outlines of one board.

1.(optional) Use a nibbling tool to cut out the rough shape of your PCB

2. Use a jigsaw to follow the outline of your PCB(s)

3. Use a sanding block, a file or a discsander to give your board(s) a nice finish.

Step 13: Now You Have Your Very Own Printed - Circuit - Boards

You are done!

That´s how simple it is to make custom printed circuit boards at home.

As you can see in the pictures the quality is quite nice. There are some tiny imperfections which are caused by the resolution of my inkjet printer.


Thanks for your attention!

I hope you like this Instructables. If you have any questions share them in the comments and I will answer them as soon as possible.

If you make a PCB with the help of this instructables post a picture in the comments - I´d love to see your results.

Stay safe !

Comments

author
kimseymd (author)2016-12-10

Seems like all of these printed circuit boards use a laser printer which is expensive to buy and maintain. When are they going to make them for an ink jet printer? Wishful thinking:)

author
TechnicalKid (author)kimseymd2016-12-10

I´ve only printed the top layer with a laser printer, the film for the solder stop mask got printed on an inkjet printer.

usually I only use an inkjet printer and it works as well.

author
Shahid Khattak (author)2016-12-05

Great effort man. Thanks for nice instructable

author
ZeeshanR3 (author)2016-11-24

great great effort man,

thanx

author
JacobZ1 (author)2016-11-22

I've tried this method before, but I've never had the greatest of results. I had good results once, but couldn't seem to duplicate them. Not sure exactly what the problem was, but it just never made me happy with the results, especially considering the time it took to do it. I ended up going back to toner transfer and I get much better results. Your printer will make a huge difference. I really wish there was a better solution for plated through-holes.

No matter what, this is great for hobbyist circuits, but I'd much rather pay a board house for something professional if I were to plan on selling it. Great Instructible, though.

author
sb4 (author)JacobZ12016-11-23

Yes, I wish there were a much easier, less messy process for making pcbs. What we really need is a "printer" that lays down copper on some sturdy stock. Or a computer driven milling machine that can cut away copper quickly. These chemical methods can make beautiful boards, but the hassle is high, especially disposal of toxic waste.

author
TiainenA (author)sb42016-11-24

Well milling machines are fairly common and while not something one might have at home (usually such machines on the kitchen counter are cause of conversation with one's spouse) local hacklab/hobby-club might have one. Those are quite easy to operate.

author
Steinzel (author)2016-11-23

I used to make PCB's and at the same time I was into B+W photography and developing my own film. I found by accident if I saved my OLD B+W developer I could put my circuit boards into a tray all at once and pour old developer on them, swish back and forth for a few minutes. The silver in the developer would silver plate all of the copper quite nicely. After you use up all of the silver in the developer then dispose of it properly.

Make sure your PCB's are VERY clean before you do this. Rinse the boards thouroughly after they are plated.

author
TechnicalKid (author)Steinzel2016-11-23

Great idea!

author
FrancescoK2 (author)2016-11-22

That's professional grade stuff right there!

author
TechnicalKid (author)FrancescoK22016-11-23

thank you

author
preschau (author)2016-11-22

You can also remove the photo-resist with methylated spirit (Denatured alcohol) or Isopropyl alcohol.

.

author
TechnicalKid (author)preschau2016-11-23

Yes but i´ve got acetone at home and it works quick and clean so I use it

author
john henry (author)2016-11-22

way better results than just putting tape on it or ironing on printer toner and tossing it into an etching bath.

author
TechnicalKid (author)john henry2016-11-23

Yes i think so too thank you

author
throbscottle (author)2016-11-23

Aieeeeeee! Just as I was writing my own pcb Instructable, you go and write this really good one!
Well done anyhow, voted ;)

author
Steinzel (author)2016-11-23

Nice! Thanks!

author
Breugel (author)2016-11-23

Hi Kid,

Beautiful presentation, we need more guys like you. I am making home prototype boards for the past four years and if I may, let me add some suggestions.

Temperature, try to work with an ambiant temperature of at least 18 degrees C for the liquids.

I buy my boards without sensitive film on it (the sensitive one are VERY expensive here (South Africa).

I use sand paper grid P1000 to clean the copper layer, then a lint free paper with acetone to obtain a perfect base for the sensitive film (lint free to avoid dust on the board).

Then I sensitize the copper with "Positive Resist" from ITW Chemische Produkte.

I dry the film in my self build dryer at +- 70 degrees C for 20 minutes and let it cool down.

I print the circuit on a translucid paper (A4 tracing paper) mirror image with a lazer printer to obtain the tracks and pads in a nice dark colour.

I then expose them in my self build UV box for 7 minutes.

The fluorescent lights must be the light blue tubes, the one used for moskitoes killer and not the dark one used in night clubs.

I then plunge my exposed board in a solution of +-7 grams of caustic soda (the crystal one) mixed with 1 liter of water.

The tracks will appear darker within 1-2 minutes and the exposed part will dilued.

I then etch the board in Ferric Chloride until it is perfect.

I then clean the board with acetone to remove the dark traces and voilà.

The whole process take less than 1.5 hour.

Drill, populate, test.

Eric

author
nqtronix (author)2016-11-20

Wow, these are some of the nicest self made PCBs I've seen so far. Lately I've decided I don't want to go through the hassle, especially with double sided PCBs, so I order them straight from china. They do get close to your quality, which is fine for me :)

author
avramreddy (author)nqtronix2016-11-22

Hi nqtronix:

Good to know that you order from China. Appreciate if could you share the contact details. Also it will nice if you can share some PCB pics that you got from China. My email ID - avramreddy@gmail.com.

Thank you.

author
TechnicalKid (author)nqtronix2016-11-21

Thank you !

author
keeboudidoz (author)TechnicalKid2016-11-22

Excellent tutorial ... this is how we rolled more years ago than I care to remember! No CAD in those days, we used the 'dot and tape' + scalpel method with a smattering of Letraset, all at 200% size which was then reduced down to 100% using a photographic method. The etching etc. was the same though we didn't do the solder resist either.

author
askjerry (author)keeboudidoz2016-11-22

OMG! Someone else knows about Letraset... today's "kids" will never know... HOURS to lay out a board... trying not to get the little cracks which meant you had to flow solder over them...

Did you know that you can STILL GET them?

author
techspec (author)nqtronix2016-11-22

Ditto what natronix said. These are incredible quality!

author
tictag (author)2016-11-22

Best DIY PCB's I've ever seen.

author
TechnicalKid (author)tictag2016-11-22

Thanks

author
askjerry (author)2016-11-22

EXCELLENT INSTRUCTABLE !

I've made circuit board for years... but have not done the solder mask or tinning... I didn't know you could get a solution to coat the copper like that... excellent tips!

Thank you!

Jerry

author
RobertZ7 (author)2016-11-22

Hey, can you add a list of all the tools, chemicals and gadgets you bought from for this project? Thanks.

author
TechnicalKid (author)RobertZ72016-11-22

Hi, thats a bit difficult because I bought most of the chemicals and tools in local shops.

Are there any tools or chemicals you dont know how to get in your country ? I could do some research for you

author
RobertZ7 (author)TechnicalKid2016-11-22

I want to know where you got the transfer paper and printing protective film from.

author
TechnicalKid (author)RobertZ72016-11-22

you can buy the printable films on amazon

for inkjet printers

for laser printers

author
RobertZ7 (author)TechnicalKid2016-11-22

Thanks!

author
hsanchog (author)2016-11-22

After many years working with printed circuits I came to the conclusion that sodium persulfate is the most comfortable and easy to handle how transparent the resulting solution can be controlled much better than with ferric chloride the end point of the attack

author
TechnicalKid (author)hsanchog2016-11-22

That´s the reason why I have decidet to start etching with sodium persulfate

author
CarlaG41 (author)2016-11-22

The UV exposure part is always tricky, getting correct time etc. If you have a laser printer then you can use film from Maplin, print to film, iron onto plain copper board, etch. Much quicker and simpler, you can easily make double sided by having 2 films joined like an envelope with plain copper double sided board slid in between for ironing.

You use laser printer to print on standard paper, iron that onto plain copper and soak off paper, but so far I've not had good results with this.

I use Ferric Chloride for etching (available from Maplin or Amazon).

But these are niceties, overall very good instructions.

author
15ashworthh (author)2016-11-22

Where can I buy the chemicals from?

author
TechnicalKid (author)15ashworthh2016-11-22

You can find them all at amazon

author
supernoodle2014 (author)2016-11-22

Thanks a lot. I had no idea what to use or how to use it to make that green protective layer. They all look like you ordered them for $$$.

author
penguin4hire (author)2016-11-22

I love this statement at the end, "That´s how simple it is to make custom printed circuit boards at home."

Incredible work I must say. Looks very professional. You must do this for a living.

author

Thank you

author
jwhitten (author)2016-11-22

That is absolutely awesome. Probably the very best home-made DIY boards I've ever seen. Kudos! And thanks for the write-up.

author
TechnicalKid (author)jwhitten2016-11-22

Thank you

author
dblancett43 (author)2016-11-22

Awsome

author
krokkodillo (author)2016-11-22

Is there any other way to design pcb's without the etching process?

author
drj-research (author)krokkodillo2016-11-22

hai - yes there is - major requirement steady hand and patience

abrade the pcb copper , cover with masking tape - ( press down hard - to exclude air ) draw circuit cut out the parts so that the copper track shows through , paint with enamel based ( car touch up ideal ) - let "dry" - edge around with small sharp knife - take off remaining masking tape

The etchant I used was Ferric Chloride - with drop of meth spirit

DRILL HOLES FIRST

author
Juan BtaT (author)2016-11-22

Hi,

Great job! How do you do circular traces?

author
TechnicalKid (author)Juan BtaT2016-11-22

the circular traces are a experiment. I´ve tried to make a small heating element (wich actually works ;) )

I´ve made them with the on pcb coil designing tool of eagle.

author
glynnj (author)2016-11-22

Really impressive quality. Thanks for sharing.

author
beic (author)2016-11-22

Really nicely done! ;)

author
electronic_artist_ (author)2016-11-20

nice and clean etching ???

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Bio: I am 15 jears old and from Austria near Germany, i'm interested in electronics chemistry and physics. I do my best to upload some ... More »
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