Etch your own circuit board. (lots of pics)

Forum 2005-2010 (read only) General Frequently-Asked Questions
#1

Hello all!

I am in the process of etching my own custom breadboard arduino PCB. I felt that it would be appropriate to share my experiences with the crowd :slight_smile:

Note that this is not my first time at bat when it comes to etching. I have made about 8 boards so far and have had a lot of fun doing so :slight_smile:

The process is actually fairly simple (after the layout and routing part which can be a real pain in the rear end). My process consists of 12 steps:

  • Printing your board layout on photo paper
  • Affixing the printed photo paper TONER DOWN onto a CLEAN PCB blank
  • Ironing the heck out of the bundle of paper and pcb to transfer the toner to the board
  • Peeling and washing the paper backing off the board.
  • Inspection and repair of any bridges (due to too much pressure) or breaks (due to too little pressure)
  • ETCHING!
  • Post etch inspection.
  • Clean toner from etched board
  • Drilling :frowning: (worst part in my opinion)
  • Apply Silk Screen layer (using same steps as initial toner transfer ā€“ optional)
  • Coating with Varathane or other protectant (optional)
  • Soldering!
    I will take pictures of my progress from ironing to soldering and will be posting them as replies to this thread as I go (currently at the drilling stage).

I hope you enjoy my ā€˜guideā€™ and please feel free to ask any questions you have. While still a novice, Iā€™d like to think the final products speak for themselves :slight_smile:

#2

Dont forget to mirror your image, I made this mistake the other day :D

#3

LOL, No kidding... I have yet to make it all the way to etching with a backwards layout, but I have printed on photo paper before I realized :)

For the record, you DO NOT have to mirror the layer if you are etching the back of the board. However you WILL have to mirror if you are etching the top side (or applying the silk screen).

Let me start the picture parade with some shots of the ironing:

Bundle of photo paper and blank PCB I set the iron on medium (i've actually opened it up and took out the heat selection knob, so you cannot even change it) Prepare your workstation! Place the iron onto the board and leave it for Three minutes to pre-heat the toner and board Apply FIRM but EVEN pressure across the whole board. Move the iron around slowly and try to move it in the direction of traces to limit the amount of 'squeeze out' you get on thicker traces. You'll know when you're done when you can see the traces through the back of the photo paper Use "Steamin' HOT" water and fill a container enough to cover the board. Let sit for 5-10 minutes to allow the paper to soak through. Start peeling off the paper backing -- don't be afraid to use some force, the toner isn't going anywhere. Finished cleaning off the paper Inspect the toner to ensure proper coverage and be on the look out for bridges or breaks (lower left area) Repair any problems by scraping away toner with a sharp tool or using an etch resist pen (or Sharpie brand permanent marker). Get your supplies ready to etch... Remember, it's always better to be safe than sorry! Use a 'double boiler' type of setup, with "Steamin' HOT" water in the outer container, and the etchant in the inner (Ferric Chloride in my case -- yucky stuff!) Dump the board into the FeCL and agitate the mixture to ensure good etching. It took about 25 minutes for this board, but the etchant was used a few times already (time to dispose of safely and refill!) Etched Board! Get your acetone ready to clean off the toner from the traces Clean board! Close up of repairs from earlier Get your drill bits ready. Ready to drill!

Stay tuned for more pics!

#4

Something to note: Don't put the ferric chloride in any metal container, or use any metal instruments, or dump it down a metal sink or metal pipes (not that you should do the last two at all!). Ferric chloride will eat up all that stuff, and it stains badly - really bad stuff.

#5

Oh for sure for sure! I did link to th MG FAQ on disposal, however I will quote their page here to make sure the information gets out there... It's beyond simple to make it safe to dispose, but if it's not done, it can wreak so very much havoc on the environment... Copper Ions are NOT mother natures friend!

Q. How do I dispose of Ferric Chloride Solution? A. There are two ways:- Contact your local Hazardous Waste Disposal Company - The solution must not be put down the drain because of residual copper ions left in it. To make it safe for disposal, you can add sodium carbonate (washing soda) or sodium hydroxide to it to neutralize it, until the pH value goes up to between 7.0 and 8.0, testing it with indicator paper. Copper will be deposited as a sludge. Allow the sludge to settle, pour off the liquid, further dilute it with water and then it can be poured down the drain. Collect the sludge in plastic bags and dispose of it as required by your local waste authority.

#6

I <3 my Cupric Chloride in an Aqueous Hydrochloric Acid Solution. I know itā€™s probably not any better for the environment, but at least itā€™s pretty much indefinitely reusable, and itā€™s GREEN (colored)!

#7

Yeah, cupric chloride is my goal... as soon as I can find the ingredients, and I've used up my supply of FeCL will most certainly switch. The re-usability plus the fact that it's translucent (you can see the the board in the etchant) makes it the best etchant I've been able to find..

More Pics!!!

Drilling Completed!

Preparing Silk Screen Layer

Printed silk screen layer MIRRORED!! onto photo paper, just as before

I then marked the size of the board, for the next step

I've found the best way to trim down PCB (1/16") is to use a sanding wheel on the dremel.

Carefully align the cut down PCB onto the silk screen photo paper and tape it up as you did with the previous ironing step

Ready to Iron!

I won't waste time by showing you the washing process again, so here's the final product. Not the best I've done, a little too much pressure caused a little bleeding of letters, but it is sufficient. More importantly, the pin numbers are readable.

Getting ready to solder! Start from the center out, and smallest to tallest.

20 minutes of soldering later, the final (albeit "fluxy") product!

I soak the board in a little bit of 99% isopropyl alcohol and use a tooth brush to clean up the sticky flux mess.

All Done!

How it will look on the bread board:

I made another quick video to demonstrate the final product. It is (so far) working perfectly! It is currently being uploaded and processed by youtube, I will update this thread when it is done.

Comments, questions, concerns? Reply!

#8

I created an imgur album for this thread, you can see all the pictures (in original resolution) plus a few more that didn't make it to the post:

http://nickvd.imgur.com/etching_your_own_circuit_board

#9

Here's the video: http://www.youtube.com/watch?v=j5dLYW6P1sc

#10

I use photo-etch with resist-coated boards. Transparencies are printed with a cheap HP inkjet printer, and I use a simple home-made UV exposure unit. I get excellent results - 8/8 mil tracks if I need them (I've done 5/5 mil as an experiment), but I usually use 10/10 or 12/12.

#11

Hi nickvd,

I use the same process as yours to etch my PCB. and I also use UV solder resist ink to add a protective layer on my PCB:

I've wrote the process in another thread, for your referrence: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1281707671/3#3

;)

#12

Nick, where do you live (country)?

If you're in the USA, you can pick up 1 gallon of Hydrochloric Acid at home depot or Lowes (I got mine at Lowes). It's more than you'll ever need! I wish it were legal to ship it. If it was I'd certainly send you some.

#13

I'm in Southern Ontario Canada. I've checked lowes briefly, but couldn't find it, what department is it likely to be in? The hydrogen peroxide is the easy part :)

#14

Try a builders merchant, it's often used for cleaning brickwork. That's where I get mine.

#15

Hydrochloric acid is also the acid sold to doctor the pH of swimming pools.

Note that most etchants, including their FUMES, will happily convince many metals that are normally considered ā€œstainlessā€ (Stainless steel, chrome, copperā€¦) to corrode. This is particularly a problem with the CuCl and HCl/H2O2 etchants, since theyā€™re normally used with an aereator that kicks up a lot of fumes and/or microdroplets :frowning:

1 part HCl added to 1 part ā€œdrugstoreā€ peroxide seems like a good starting point. I dissolved a bunch of scrap copper in mine to get the CuCl2, but I gather that the acid/peroxide is a pretty good etchant all by itself.

#16

Yeah, check the pool section. That's where it is.

Here's the instructable I used to make mine. It worked great :):

http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

#17

Yeah, I saw that same instructable myself (saved it to pdf just in case as well). I only started with FeCL because I was anxious and couldn't find the HCl quick enough :)

Next time I'm in the area of the appropriate shops I will most certainly pick some up for when I finally use up and dispose of all my FeCL

#18

Iā€™ve been using the Pool Chemical based etchant versus Ferric Chloride for nearly 10 years nowā€¦ I much prefer itā€¦ I STORE my chemicals outside since I my container wasnā€™t fully closed once and my workbench tools became quite rusted.

#19

I STORE my chemicals outside

Me too. Mostly because my mom doesn't trust me ;D.

my container wasn't fully closed once and my workbench tools became quite rusted.

facepalm I had wondered why my soldering iron got all rusty randomly. I just went and checked and the HCl/H202 mix was a little crossthreaded :(.

#20

Very Helpful thanks :)