Silver/nickel circuit pen lifespan

Discussion in 'General Electronics Chat' started by ntt, Sep 13, 2018.

  1. ntt

    Thread Starter New Member

    Apr 14, 2017
    2
    0
    Hello,
    I think of buying a conductive pen, possibly Chemtronics cw2000 nickel pen (as it is in nice < 20e price range).
    I would use it quite occasionally, it'd be more like "a handy tool to have in desk drawer" if I happen to need it.

    BUT, what is unclear to me is their lifespan. Datasheet says its shelf-life is 1 year and when opened, it decreases to 6 months, after which "performance cannot be guaranteed". That doesn't sound like much.
    I guess a clogged tip could be opened with some solvent, but could a pen really dry/degrade "beyond repair" in some meaningful time?

    Would be sad to use the pen for couple of tiny traces now, just to notice year or two later it doesn't work anymore. :(

    Do you guys and gals have any experiences on this?
     
  2. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    3,157
    2,191
    The 'unopened' shelf-life owes principally to 'vehicle' stability and is typically very conservative (I've experienced no difficulty with such products following more than 5 years unopened storage in a rather warm loft -- Whereas the 'opened' shelf-life anticipates liability to 'evanescence' of volatile compounds...

    My advice -- Once opened, merely store the pen/applicator in a neoprene-stoppered borosilicate test-tube and you're good for years -- indeed the better part of a decade if stored (thus contained) in a residential refrigerator (i.e. at ≈ 4.5°C)...:cool:

    Source: Long experience:)

    Hope to have been of assistance!

    Best regards
    HP
     
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  3. Aleph(0)

    Active Member

    Mar 14, 2015
    580
    909
    @Hypatia's Protege I totally agree! Also that goes for 2-part adhesives, heat sink paste and electronics silicone too:cool:!
     
  4. dl324

    AAC Fanatic!

    Mar 30, 2015
    8,139
    1,959
    I recently came across a Circuit Works conductive pen (silver) that I purchased in the 90's. It's dried out.

    I have a CircuitWriter (looks very similar to the Circuit Works pen) that I purchased about 10 years ago. It's also dried out.

    In my case, both pens turned out to be single use. I won't be buying any more unless I have a job big enough to use up a significant portion of the ink in a short time.

    Lately, I'm more inclined to use a piece of copper foil adhesive. It's sold with electronics stuff, but it's much less expensive if you buy from a stained glass supplier. The tape intended for electronics might have a conductive adhesive. When I use the tape, I affix with the adhesive backing, then I solder. A repair I did 10 years ago is still holding up.
     
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  5. jpanhalt

    Expert

    Jan 18, 2008
    6,918
    1,434
    Agree for adhesives in tubes. With 2-part epoxies that I get in cans/squeeze bottles and so forth, not tubes, I store the once-opened hardener under argon. The resins are usually OK without that precaution.

    As I use the same argon to preserve wine that I have opened, the incremental cost is nil. Great thing about argon is that it is much heavier than air, so I just flush with a gentle stream and put the cap on.
     
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