What went wrong with my pcb?

Discussion in 'The Projects Forum' started by eddie6775, Jan 6, 2013.

  1. eddie6775

    Thread Starter New Member

    Jan 6, 2013
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    Hi everyone, I've made pcb's before and do pretty good with a sharpie and rub on traces but I want some thing more. I'm sure most people here have; so I've been attempting the toner transfer method of pcb making.

    Every thing goes nicely until I etch the board. Here's what I've been doing:
    1)use Eagle to make the schematic and board picture and print accordingly
    2)Print on CLEAN regular non gloss printer paper with an old brother hl1440
    ...(I suspect that the paper could be the problem)
    3)pre heat iron, clean copper clad with course scotch bright and then nail polish remover
    4)put iron on clad for 30 seconds and follow with the picture I want to transfer
    5)apply heat with iron for 20 - 30 seconds per heating session remove and roll as hard as i can with a roller bearing w/ handle (looks like a small pizza cutter)
    6) after i can start seeing the traces easily through the paper I let it cool and then soak it for an hour or better to soften the paper.


    Here's what's happening though. The paper comes off very easily, and looks ok, but when I etch the board it looks as if it was hit with a wire brush.

    I also suspect the copper clad. It was sitting in the barn for 20 years before I inherited it and I wonder if it might be oxidized to the point of uselessness?

    So there you have it, I've thrown a ton of variable at you and want an answer darn it! lol.

    Any advise would be greatly appreciated, and thanks in advance!
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    What is your enchant? I had this exact same issue with ferric chloride. I switched to a solution of hydrogen peroxide and muriatic acid and my problems went away.


    See Bill procedures on making PCBs in the completed projects forum.
     
  3. eddie6775

    Thread Starter New Member

    Jan 6, 2013
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    I've been using the ferric chloride. I'll have to try your solution. ..Wow, Bill makes it look easy! I wonder what causes the ferric chloride to to that. Is it more aggressive?
     
  4. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    My theroy is that the FC is not strong enough for the copper. It starts eating at the toner then pitting the copper underneath. Be careful with Bill's solution and good luck.

    BTW I tin with Liquidtin and that vastly improved too.
     
  5. eddie6775

    Thread Starter New Member

    Jan 6, 2013
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    I've heard of tinning but I'm not sure of the how or why of it. I'll have to do some reading on that one.
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    Be sure to clean your copper clad boards before you start. Fine steel wool or, probably better, a green scouring pad work well. Rinse off with clean water and dry with a towel before you begin the patterning process.

    I've only used FC and have had very few problems. But one thing that is pretty important is to agitate your etchant solution. You can do this manualy by just rocking the tank back and forth but some type of mechanical agitator or, even better, circulating pump will yield better results. Also, if you heat the etchant it will etch quicker, giving less time for undercutting. I used a cheap IR heat lamp and it worked nicely.

    Now, I'm not a big fan of the toner transfer method and prefer to use pre-sensitized boards. I made the switch when making a bunch of two-sided boards using 50mil pitch parts with about 200 vias that had to be small yet lined up adequately to connect with scrap component leads.
     
  7. eddie6775

    Thread Starter New Member

    Jan 6, 2013
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    I don't swish the container around but instead use a small acid brush to gently sweep the face I'm trying to etch. Do you think that might be my mistake? Perhaps I shouldn't touch it at all. and just swish the container?

    Is it expensive to use the boards and the set up you use? I've heard the method you use comes out better in general.
     
  8. j taylor

    New Member

    Nov 4, 2012
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    it could also be the nail pollish remover if its not pure acetone then it will leave a film on your pcb that stops the toner sticking
     
    Last edited: Jan 8, 2013
  9. eddie6775

    Thread Starter New Member

    Jan 6, 2013
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    It has water and fragrance in it. possible. I seem to have set up the perfect failure! I DO know I'm gonna try This again. I'll post the results for any one else who might be interested in learning this.

    I guess that's why they call it art work!
     
  10. WBahn

    Moderator

    Mar 31, 2012
    17,757
    4,800
    I would avoid any mechanical contact with the etch resist. The presensitized boards are not super cheap, but they aren't outrageously expensive, either.
     
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