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Question about PCB copper trace protection — Parallax Forums

Question about PCB copper trace protection

VaatiVaati Posts: 712
edited 2010-07-26 21:04 in General Discussion
I have made a few circuit boards for projects before, and one of my most useful projects uses a circuit board I etched. Sadly, the copper traces are starting to corrode, and since a few of them etched a little too long, they are dangerously thin. Is there a way to "laminate" the boards with a protective coating so the boards won't corrode? I do have some polyurethane that I got from home depot -- would that do the trick?

Thanks.

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Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-07-26 17:09
    A conformal coat like this one should do the trick. You spray it on after the board has been populated (and any connector contacts masked).

    -Phil
  • W9GFOW9GFO Posts: 4,010
    edited 2010-07-26 17:31
    I use clear lacquer on aluminum parts, I would think that it would work on a circuit board to keep the copper from oxidizing but it is not something that I have experimented with.

    Rich H

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    The Simple Servo Tester, a kit from Gadget Gangster.
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2010-07-26 17:35
    I have seen lots of ideas across the forums, etc, for coating copper traces, but these are my choices:

    ITW Chemtronics CircuitWorks Overcoat Pen (this is the correct stuff to use to coat exposed copper by hand)
    http://forums.parallaxinc.com/webvia.techni-tool.com/VIA/products/237CH206 $19 for a pen, comes in clear and green (we use green at work when we do PCB repairs like replacing pads or traces)

    ITW Chemtronics Konform SR Conformal Coating Spray, aersol can, (good to coat everything on the board for protection from moisture, etc)
    http://forums.parallaxinc.com/webvia.techni-tool.com/VIA/products/237CH012 $30 a can, but good coverage.

    For normal hobby use at home, I tried an old bottle of my wife's Nutra Nail Nail Hardener that she was going to toss . It's like a very hard clear nail polish available at Walgreens, Amazon, Rite-Aid, etc, for about $4. Any clear nail polish will work, but the nail hardener type seems to caot better and be more resilient (doesn't chip or flake away as easily)
    www.amazon.com/Nutra-Nail-Green-Tea-Hardener/dp/B000EGMBM0/ref=sr_1_1?ie=UTF8&s=beauty&qid=1280163293&sr=1-1

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    Andrew Williams
    WBA Consulting
    PowerTwig Dual Output Power Supply Module
    My Prop projects: Reverse Geo-Cache Box, Custom Metronome, Micro Plunge Logger
  • VaatiVaati Posts: 712
    edited 2010-07-26 17:43
    Phil, that looks very convenient, but I prefer a little more DIY and to be able to use stuff I already have.

    W9GFO, this is kind of an off-topic question, but do you use aluminum very often? If so, do you have any idea where I can get 1/4" inner diameter aluminum pipe for a reasonable price? If so, send me a PM so this thread doesn't get way off track.

    Andrew@WBA Consulting, thanks for the links. I'll see if I can take an old bottle of my mom's nail polish. smile.gif

    I'm going to test polyurethane shortly on a test pcb and see if it can withstand ferric chloride afterwards.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    MCU Projects·- my new site where I will be posting all projects, code, etc.

    Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!

    SD Card Adapter·- Add extra memory to your next Propeller project with ease!
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2010-07-26 17:49
    WORD OF CAUTION: Be cautious of outgassing that can occur with whatever chemical solution you choose, especially with display devices. I recently crippled my $65 uOLED display when I used a CA based glue to glue plastic standoffs to a case. I used the display to line up the standoffs to apply the glue, but should have removed it while it cured. During curing, CA releases various vapors, some of which absorbed into the side of the uOLED glass. Now, the left side is dimmer than the rest and it will cost me $30 to purchase the LCD to replace it. That was not a happy day.....this is why my handheld Propeller GPS that I was showing off at UPEW is not on the forums.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Andrew Williams
    WBA Consulting
    PowerTwig Dual Output Power Supply Module
    My Prop projects: Reverse Geo-Cache Box, Custom Metronome, Micro Plunge Logger
  • LeonLeon Posts: 7,620
    edited 2010-07-26 18:19
    I use photo-etch, and remove the resist by rubbing with a piece of kitchen towel moistened in IPA. I find that the very thin resist residue that is left on the copper protects it very well.

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    Leon Heller
    Amateur radio callsign: G1HSM
  • W9GFOW9GFO Posts: 4,010
    edited 2010-07-26 20:07
    Vaati said...

    W9GFO, this is kind of an off-topic question, but do you use aluminum very often? If so, do you have any idea where I can get 1/4" inner diameter aluminum pipe for a reasonable price? If so, send me a PM so this thread doesn't get way off track.

    This is the Sandbox after all, I have used Online Metals a few times but my best source was Boeing Surplus in Kent, WA. Too bad it closed. [noparse]:([/noparse]

    Rich H

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Simple Servo Tester, a kit from Gadget Gangster.
  • W9GFOW9GFO Posts: 4,010
    edited 2010-07-26 20:11
    Leon said...
    I use photo-etch, and remove the resist by rubbing with a piece of kitchen towel moistened in IPA. I find that the very thin resist residue that is left on the copper protects it very well.

    Now that's a use for beer that I haven't heard before!

    en.wikipedia.org/wiki/India_Pale_Ale

    Rich H

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Simple Servo Tester, a kit from Gadget Gangster.
  • LeonLeon Posts: 7,620
    edited 2010-07-26 21:04
    It's isopropyl alcohol, unfortunately.

    India Pale Ale (the other IPA) was so-called because it was the only beer that could be shipped to India in the time of the British Raj that would still be drinkable when it got there. It was basically the same as the bitter that is still quite popular today. I remember being told that on a student visit to the Bass brewery in Burton-on-Trent, over 50 years ago. Following the visit we were given as much Worthington E as we could drink in 30 minutes. It was straight from the barrel, and even nicer than the E served in our favourite pub, which was pretty good.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
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