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Another Wacky Idea for Making Circuit Boards

Discussion in 'Electronic Design' started by D from BC, Jun 7, 2007.

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  1. D from BC

    D from BC Guest

    Getting photoresist chemicals...ugh...That's not on every store
    shelf.. :)
    Of course there are presensitized PCB's..
    And there's the toner transfer methods..
    And there's EDM, routing and sandblasting.

    How about using UV adhesive... :p

    I could spread UV adhesive on a PCB...
    Then put a transparency on top with the PCB pattern and then put a
    heavy glass plate on top of that.
    Expose to UV..
    Rince in _________.
    Etch
    Then strip the board with _______.

    I don't know the blanks yet..

    UV glue is about $30.00US/25cc. (Hughes) or $8.00US/2cc on Ebay

    Can I get rich? $$$ :)
    D from BC
     
  2. Guest


    How many PCBs could you have made at Olimex by now? With the time and
    money you spent tilting at windmills? Just curious.

    You could print glue with an inkjet-type printer and coat in copper
    pigment powder available at good artist supply houses. Still won't
    give you plated through holes or even a garantee of alignment between
    the layers. But I'd like to hear about what you'd do with copper
    pigment.
    (PS test to see if it's really copper by tossing it into a flame.
    Green is the color you want)
     
  3. Robert Baer

    Robert Baer Guest

    How about the old-fashioned el-cheapo way: eggwhite sensitized with
    potassium dichromate?
    Develop with the universal solvent: water...
     
  4. John Larkin

    John Larkin Guest

    Cool. Negative exposure, gold plate the traces, strip resist, and use
    the gold as etch resist for the copper. Make pot au creme with the egg
    yolks.

    John
     
  5. D from BC

    D from BC Guest

    I've never heard of that..Does it work well?
    Also...I think powdered eggwhite exists and would that work?
    D from BC
     
  6. James Arthur

    James Arthur Guest

  7. D from BC

    D from BC Guest

    I did a little GoogleFu on this and found that gelatine can be used.
    Wikipedia mentions animal protein.
    D from BC
     
  8. D from BC

    D from BC Guest


    I looked at:
    http://www.patentstorm.us/patents/4707433-description.html
    Casein is mentioned and I believe that's what's in Elmers white glue..
    So maybe Elmers white glue + cancer causing potassium dichromate =
    negative type photoresist... Wonderful! :)
    When I was a kid..that cow on the label was always a mystery to me..
    Cow bone glue.. :p

    It's kinda like the potassium dichromate is the reverse of sunblock :)
    UV SPF -40 for extra burn :p
    (note the negative sign.)
    D from BC
     
  9. All this reminds me of using potassium dichromate and sulfuric acid to
    make "chemist's cleaning solution," which I'd use to clean glassware.
    Wonderful stuff. To dispose, I'd have to reduce to chromium-III with
    sulfite salts and then neutralize that stuff with sodium bicarbonate
    or hydroxide (exothermic.)

    Jon
     
  10. Rich Grise

    Rich Grise Guest

    Actually, Elmer was Elsie's "husband" in the Borden's Milk logo. Their
    "daughter" was Beulah.
    ....
    Just did a quick search, and apparently there is no such thing as
    "Borden's Milk" any more, just archival stuff. )-;
    ....
    Did a little more in-depth search, for images this time, hoping to see a
    logo, and imagine my surprise - Elmer's glue is made by Borden!
    http://www.officedepot.com/textSearch.do?uniqueSearchFlag=true&Ntt=elmer's+glue

    Cheers!
    Rich
     
  11. Robert Baer

    Robert Baer Guest

    Powdered eggwhite works just as well.
    The problems are that the "shelf life" of sensitized board is maybe a
    week or two, and the surface is sensitive to scratching (it is soft
    eggwhite).
    This "trick" has been around since at least the 1970's.
     
  12. D from BC

    D from BC Guest

    I'll keep an eye out for some potassium dichromate.. I think I can get
    it at photo supply shops..It might be pricy from the local chemical
    distributor..

    ....well this thread is about to fizzle out..
    I'd like to lastly mention that nobody made fun of the obvious flaw
    that UV glue would glue the transparency to the PCB..
    It might be very difficult to remove!

    ....but maybe some spray PAM or spray silicone on the transparency
    might help..
    D from BC
     
  13. Rich Grise

    Rich Grise Guest

    Maybe going through all these gyrations is fun for you, but it sounds like
    a PITA to me.

    I like the idea of printing the artwork on my dot-matrix, xeroxing it onto
    coated paper, and ironing it onto the board. The only chemical involved is
    the etchant, and you don't have to be in the dark to prepare the resist. :)

    Cheers!
    Rich
     
  14. Robert Baer

    Robert Baer Guest

    There have been a few XEROX and other printers that hav a flat
    (paper) pass-thru, and accept fairly thick "paper".
    AFAIK all of those are useable for *direct* printing of the pattern
    onto the PCB.
    Some of the first lazer copy machines were like that, and Lexmart
    "recently" (2-5 years ago?) had one like that.
     
  15. Ecnerwal

    Ecnerwal Guest

    As I've said before, old flatbed pen plotters, with a resist ink pen
    also worked well for direct printing of resist. Plot, dry, etch.
     
  16. YD

    YD Guest

    Dot-matrix? How's the resolution with it? Do you print expanded and
    reduce the copy? I recall having done that with some artwork stuff at
    a time when laser-printers were affordable only to the rich and
    wealthy.

    Personally I run photo-paper through my laser-printer and then do the
    thermal transfer thing. Takes a bit of experimenting with different
    brands and types but now I've found a good combination that lets me
    successfully do 0.1 mm (4 mil) traces. Not that I use such fine pitch
    for anything but lettering, standard is 0.4 mm (15 mil). Bit of a PITA
    to remove but the result compensates.

    - YD.
     
  17. D from BC

    D from BC Guest

    Toner transfer ...ugh.. :p
    I ordered dry-film photoresist to put an end to that....
    D from BC
     
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