PCB etch resist pen

Discussion in 'General Electronics Chat' started by rjjenkins, Nov 12, 2012.

  1. rjjenkins

    Thread Starter Member

    Apr 16, 2011
    102
    2
    Hello
    I haven't made a PCB board for 30 years or more but I don't remember it being hard. Now though, I can't stop the acid etching through the lines I've drawn. I'm using ferric chloride, and a pen which is sold for this purpose but which appears to be identical to the ones used for writing on CDs. It doesn't seem to be acid-resistant enough. I'm sure I used to have a pen that easily withstood the acid but I'm not sure how to find one now. I think I need something more like nail varnish, but in a pen, not a pot.
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    Why are you drawing lines? Purchase a laserjet printer and use the toner transfer method. New laserjets are very affordable these days.

    For touch ups, you can use a Sharpie Industrial, though I have had some etching issues with those, others have had great luck.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,764
    2,534
    How I make PCBs

    There are some wide choices as to etchant too. Having said that, that is how I started with PCBs as a young teen.
     
  4. Pencil

    Active Member

    Dec 8, 2009
    271
    38
    I agree with the laser printer/waxed paper method
    being the way to achieve very good looking results.

    For a marker solution try this one. Marker. I have had good luck.
    with it using Muriatic acid and Hydrogen Peroxide as the etchant.

    When using a marker or toner transfer a few tips:

    -Scrub copper clad board using green Scotch brite pad and isopropyl alcohol.
    -Wipe board with a clean cloth and isopropyl alcohol.
    -Dry with a clean lint free cloth.
    -Avoid touching surface of board.
    -When using a permanent marker use a light touch, allow
    ink to flow without smearing.
     
  5. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    I use the black Edding 400 and the 404 for finer lines. It's pretty good, sometimes needs going over again where the lines don't look quite black enough. You can also get bottles of ink and replacement nibs for them. The nibs are double ended so if you just get the pen, you can pull the nib and reverse it if it dries up.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    If your ferric is too weak it will slowly soften the pen ink and etch through it or under it.

    Good ferric is very dark, and will etch the board in under 5 mins when properly agitated. If your etch time was much over 5 mins it is possible your FC is weak or watered down too much.

    Also really scrub the board good with fine grain wet and dry paper (I like 600) and then with a clean scotchbrite, and then alcohol clean it before using the pen. If the board is not properly prepped the pen ink won't adhere well and the FC gets under it. If the board is prepped well the pen type does not matter you can use any waterproof felt tip (Sharpie etc) and there will be no problem.

    So to sum it up; really clean and scrubbed board, nice strong FC, lots of agitation.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    heck I've used a regular black sharpie to touch up missed spots doing the toner method and it worked just fine.
     
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