Etching questions

Discussion in 'General Electronics Chat' started by Electroguy86, Nov 1, 2014.

  1. Electroguy86

    Thread Starter New Member

    Nov 20, 2012
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    http://m.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

    Question. First off I'm new to pcb etching. Always used perf boards. Tried this solution and love it! First few boards I etched took minutes with a fresh solution. I had to make another solution and dropped a board in it. It took nearly 20-30 minutes to etch a small board. Tried to mix another solution like instructable says and same thing. Slow etch. Why? Should the board be dry after rubbing paper off or could paper from the laser etcher still be on there slowing etch time down? Also, light? Could light really slow it down that fast? Heating? Can that speed it up? And I know about agitating it. Thanks!

    Oh, this is using muriatic acid and hydrogen peroxide
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Heating and agitation make a huge difference in speeding up the etching.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    Have you read my procedure?

    How I make PCBs

    I like using H2O2 and Muriatic Acid because the mix is self heating, which helps a lot.
     
  4. Electroguy86

    Thread Starter New Member

    Nov 20, 2012
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    Hmm.. I wonder what I'm doing wrong. Maybe their is some paper residue on the board im not seeing. i have been doing a mixture of 2 parts H2O2 and 1 part HCL. What if it was 1:1? The pic is of one of my first boards. Slow to etch but did do a pretty good job I think.
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    It sure looks good.
    How much heating and agitation are you doing?
     
  6. Electroguy86

    Thread Starter New Member

    Nov 20, 2012
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    No heating. I have a cheap fish pump that blows in air and I just rock it back and forth
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Heating is important. If you have a hotplate I would preheat the liquid to lukewarm. It dramatically speeds etching, for any etchant.

    If you read that procedure I posted you will note the gloves and small piece of sponge. Again, it improves the results and speed dramatically.

    Agitation works better for FeCl3, while the sponge works better for the H2O2/Muriatic Acid IMO.
     
  8. Electroguy86

    Thread Starter New Member

    Nov 20, 2012
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    I went ahead and bought a small hot plate to warm some water. And I'll try a sponge with some gloves on
     
  9. Markd77

    Senior Member

    Sep 7, 2009
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    Just a note on the board, the holes that come through from the other side to the ground plane are going to be hard to solder because you end up heating a large area of board. Most PCB software will have a special pad which looks the ones here. It will make it easier.

    hole.gif
     
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