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Epoxying over chip numbers?

Discussion in 'General Electronics' started by John Muchow, Jul 2, 2004.

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  1. John Muchow

    John Muchow Guest


    Isn't there a chance that the acetone could affect the bond between
    the IC legs and the case material, i.e., some of the acetone could
    work its way inside and cause damage? Or is the chance of that no
    greater than the possibility of damaging the chip with our Dremel?

    John Muchow
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  2. John Muchow

    John Muchow Guest

    Abrasion does the trick: sanding, milling, laser.
    Infantile...interesting choice of words. I'm finding out that this is
    a surprisingly emotional topic for a lot of people. Frank has brought
    up some great reasons for not hiding chip numbers, but there's still
    the problem of micros, etc.

    Because of the simple design of these products (it's the unique
    packaging and combination of features that separates them from the
    competition), we'd like to slow down anyone interested in copying the
    design just a bit...until they come to market. Then, we can use
    market penetration, great pricing, great tech support, etc. to make it
    not profitable (we hope) for others to use our design.

    It will inevitably happen, but if a few seconds of sanding (or
    epoxying) of our prototypes can slow this process down until the
    production models appear, that sounds like a damn good investment in
    time and money to me.

    How is hiding part numbers infantile? How is using a micro without
    posting the source code not infantile then? I'm serious.

    John Muchow
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  3. You do realise there are simple designs that will identify most logic
    chips automatically?

    Wouter van Ooijen

    -- ------------------------------------
    PICmicro chips, programmers, consulting
  4. Brane2

    Brane2 Guest

    John Muchow wrote:

    Hiding part numbers is infantile because it is major pain in the ass for
    anyone trying to service the device and because it doesn't stop anyone
    trying to duplicate it.

    It can buy you a few days at the most with the copycats and a frontrow
    seat in hell, reserved by anyone who have tried to service your product
    without full documentation and portfolio of spare parts...

    With code inside micro, it's much different thing. It is still awkward
    for servicing, but at least it is efficient against hobbyistic copiers,
    so it achieves its basic goal- reasonable IP protection.


  5. Jim Thompson

    Jim Thompson Guest

    I'm astonished at the number of people on this group who are incapable
    of reading.

    The OP said "prototypes".

    ...Jim Thompson
  6. Brane2

    Brane2 Guest

    Jim Thompson wrote:

    Same here. I was merely responding about the difference between relying
    on epoxy and using codeprotected components...

  7. Guest

    I feel the usual reason major manufacturers obliterate or house label
    parts is so that they can't be repaired, not to prevent duplication.
    Take a TV or VCR as an example. The company doesn't want them
    repaired as each repaired unit is a lost sale on a new, dispoable

    I have no issue with hiding numbers on a prototype. I find it very
    annoying though, trying to repair something with unlabeled parts.

    What kind of product are we discussing anyhow? Are these particular
    parts even likely to fail in the long term?

  8. Rich Grise

    Rich Grise Guest

    I saw a couple of guys cleaning graffiti off a sign once with laquer
    thinner, which is a lot like acetone. The sign had epoxy paint, and
    it shrugged off the laquer thinner like rainwater. I think the epoxy
    that chips are in wouldn't even notice acetone.

    Fuming nitric acid, on the other hand...
  9. John Muchow

    John Muchow Guest

    With code inside micro, it's much different thing. It is still awkward
    So, both are a PITA but because hiding chip numbers isn't as effective
    a method of IP protection, it's infantile?

    Perhaps I'm just overreacting to the word itself.

    John Muchow
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  10. John Muchow

    John Muchow Guest

    What kind of product are we discussing anyhow? Are these particular
    We've never had a failure of any of our electronic components in 16
    years so I don't have much data to offer...we've never had to repair
    anything. Someone did rip off a battery connector a few years ago,
    but he was able to repair that one himself. :)

    We've always been ready with loaners to ship overnight and postpaid
    (both ways) repair service if needed though.

    John Muchow
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  11. John Muchow

    John Muchow Guest

    You do realise there are simple designs that will identify most logic
    Yea, Mark reminded about those things. :)
    We've got some chips that aren't 74/54 (and similar series) logic
    chips (they're analog).

    If I'm not mistaken, can they use the testers in-circuit? We'd surely
    notice if anything was removed and soldered back in again.

    We are only looking for a bit more time here, not long-term protection
    from copying. We figured that a couple of minutes with the prototypes
    is worth it just to make any copycats with the right equipment really
    have to earn their keep.

    Any day I can aggravate someone who wants to steal our designs for
    commercial use is a good day.

    John Muchow
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  12. John Muchow

    John Muchow Guest

    OK, we've determined that anyone who covers chip numbers will burn in
    hell, that sanding and electric erasers work great, that Dremels work
    great (but be careful), but no one had any recommendations for an
    epoxy? :)

    Guess we'll have to keep using the Dremel for the rest of the
    prototypes. Thanks for your suggestions and advice!!.

    ....hey, is it getting hot in here?

    John Muchow
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  13. Robert Baer

    Robert Baer Guest

    Acetone has about the same effect as water; the dremel tool can do a
    lot of damage if one wants...
  14. Robert Baer

    Robert Baer Guest

    Epoxy will be of no use.
    Sanding, grinding or laser abrasion are the only effective ways of
    "hiding" (removing) part numbers.
    Use of FPGAs, PALs or micros is standard industry practice, and coding
    is usually kept in house (also standard industry practice.
    If you want to confuse the troops, add logic and linear that does no
    useful purpose, but looks like that it is being used.
    Also, put some critical traces under ICs with other traces that look
    like they are needed both under ICs and visible, that do no useful
    Try added layers with used and extra traces; blind vias, etc.

    Housesomeever, it all can be eventually decoded by someone with the
    right tools and time...

    I think that removing the legends off ICs will only pique someone's
    interest, and therby hasten the eventual "decoding".
  15. Robert Baer

    Robert Baer Guest

    FPGAs, PALs and micros all have been used in prototypes...
  16. Sal Brisindi

    Sal Brisindi Guest

    With this long discussion, we still don't know what it is...its like a
    soap opera, Who killed JR?

    Sal Brisindi
  17. Mark (UK)

    Mark (UK) Guest


    It's more like - what the hell WAS in the case in Ronin :)

    Yours, Mark.
  18. <Snip>

    If they're though-hole chips, fold the legs over and mount the chip on
    the reverse side of the board (or re-lay the PCB). Or, instead of a
    Dremel, use a sheet of emery paper flat on the desk and erase the
    markings before soldering.

  19. Julie

    Julie Guest

    How many protos are you talking about? 10s, 100s, more?

    Can you just pot the entire board? Or do you need to have subsequent access to

    Several have mentioned laser etching -- I'm presuming that you don't have
    immediate access to one of those, nor want to spend $25k for one at the
    moment... You may be able to achieve this in a cost-effective way by visiting
    your local sign/engraving shop. Most have (on-site) access to a laser engraver
    which should perform adequately well in a situation as this. You could
    probably get the cost down pretty low per piece as well.
  20. Rich Grise

    Rich Grise Guest

    To use epoxy and make it stick, you'd have to sand the chips anyway.
    But you can get a more aggressive wheel than an eraser! I work in a
    weld shop, and they have little (air-operated) angle grinders, just
    like a Dremel, but with a right angle at the business end, so you
    can use a sanding disk, or whatever it's called. :)
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