PCBs Needed NOW. Etch!

Posted by on Apr 28, 2012 in Blog, Etc | 5 Comments

I needed a board layout NOW. While I love Laen’s PCB service, I can’t wait 2-3 weeks for boards. I’d never etched boards before, but I’m always up for a challenge!
I based my procedure on a bunch of email with my friend Jon and this Hackaday post, which I started reading at 9am.
I already had a schematic and board layout. I altered the board layout to have thick traces and large pin holes so I’d be able to see better where to drill them out.
Radio Shack sells both etch solution and copper boards so off I went.
10am: Here’s a first print and a scuffed copper (scuff with green scrubbie pad, not with Brillo)



I need a LaserJet printer so that the ink is nice and thick, and also because there is a difference between InkJet and LaserJet toners. InkJet toner doesn’t work because it won’t stick to the copper, while LaserJet will chemically stick using heat. Jon was kind enough to let me come by his work after lunch to use both the LaserJet there AND their laminator. Jon printed the board print in black, cyan, magenta and yellow, leaving a nice thick layer of ink. We printed the board pattern on shiny magazine paper and regular paper both and compared results. The idea is that shiny paper will release the ink better.

Put paper on top of copper and run through laminator!


Pull paper off and inspect! Both magazine and regular paper worked pretty well.


Soak board in etch solution





Since it’s freezing outside (~45F), it takes nearly two hours to finish etching



This is a process I will definitely do again, as a board can be made in a day, or a few hours.


5 Comments

  1. mak
    May 6, 2012

    good and neat work there.

    to speed up the etching process, you can heat ferric chloride solution a little bit.(upto 45C to be safe)
    make a heater or just keep the etching tray over warm water.

    try adding water to the solution and see if it heats up or not.

    you can make a lot of copies of the same board in one day. etching shouldnt take more than 10 mins.

    note: you can use the solution again and again a lot of times before throwing it in the drain.

    Reply
  2. Andreas
    May 26, 2012

    Sophi, you can also try using a sponge with the etchant. Just rub it on and you are done in a minute or two. (I read this on instructables…) Wear gloves, but nice thing is it uses much less etchant so disposal is easier.

    Reply
  3. Jeremy
    May 29, 2012

    In my electronic classes, we stopped etching a long time ago and just milled out our boards instead with a small CNC mill. It is cleaner, faster, and in my opinion all-around easier. Just a thought for you next time.

    Reply
  4. egineer blogs
    October 24, 2012

    very old method , good info
    engineer blogs

    Reply
  5. Andy
    June 3, 2013

    Sophi, I used to do the toner transfer method for all of my boards. I now use the positive photoresist method. WAY easier and reliable and pretty quick. I’ll be putting up a post on my blog in the next week about it. It sounds more complicated that it is. You can purchase photosensitive boards and developer. You print reverse images of you circuits on transparency. Put the transparency over the unexposed board, set it under a CFL bulb for 10 minutes, throw it in a bath of water+developer and in minutes you have super-accurate duplicate of your transparency on the copper board. The developer washes away exposed photoresist and you’re left with a very exact copy of the toner image on the transparency. Exact, as in, it even picks up details from the Scotch® tape holding the board in place. Funny. Do your normal etching and BOOM! Done. The toner transfer method, in my experience and opinion, was troublesome because of the occasional toner detachment due to poorly scrubbed boards. Just my thoughts, but I won’t go back to that method anymore. FWIW.

    Reply

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