Printed Circuit Board SUPPLY SOURCES

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G-Daddy

Member
2001-10-02 6:50 pm
Baton Rouge, La
  • #1
    If you were going to make a 6" x 5" printed circuit board, using the photoresist method, what brand name and mail order supplier would you choose? Who carries good stuff, for a good price?

    I don't intend to go the full agitator / heater / uv light route, that seems a bit much to me. No, I think the hot water bath and sunlight exposure method fits my budget better. So what I really need is the boards with photoresist coating (I don't mind cutting them in half to reach my size goals), the developer, and the etchant. I'd like to think these things come in reasonable priced kits. . . So please, recommendations on brands and suppliers are welcome. Thanks everyone.
     
    jackinnj

    jackinnj

    Member
    2002-04-18 1:05 am
    Llanddewi Brefi, NJ
    tech-diy.com
  • #2
    What I use for PCB's

    I have bought boards from JDR Microdevices, Digikey, Jameco etc. Mostly, I add them on to an order when running low.

    I use the positive method -- I buy the boards in 12X12 inch size and cut what I need on my table saw. I generate the positive artwork with Ultiboard, but there is freeware which a number of folks use ( http://www.cadsoft.de/freeware.htm ). I print on mylar transparency sheets or Avery "Clear" labels. Exposure is for about 8 minutes on my fluourescent light table (for proofing negatives) but would be less in the sun. Develop for about a minute in a 3% solution of Sodium Hydroxide (yes, you can use Drano). Rinse and etch. You can do the exposure, develop under a (dim) red lamp.

    I have used the negative method, easy for me to say as I have a complete darkroom and can work with LITH materials. I think the positive method is a lot easier.

    When I have something really simple and not to large to etch I attach the piece of regular, non-photo sensitive board to a piece of mylar and run it through my HP7475a plotter -- then follow the traces with an indelible (water-PROOF) marker, etch with ferric chloride. Ultiboard allows the possibility of using the HP7475a for this purpose, but you have to fiddle a little with the end-resulting file to make it print in reasonable amount of time.
     
    G

    G-Daddy

    Member
    2001-10-02 6:50 pm
    Baton Rouge, La
  • #3
    Experiences

    Well, for what its worth, I managed to etch some circuit boards. Basically, I printed the layout to a transparency sheet on a laser printer, ironed it onto a copper clad board, and then etched away. No expensive parts, no expensive machinery. Just a plastic rubbermaid tub, a $4.00 bottle of ferric chloride from Radio Shack, some scrounged copper clad fiberglass (my job rules), and a couple hours of mindless tedium while rocking the tub manually. All in all, making the boards cost me just the etchant, and that was just 4 bucks. Way better than 150 dollars plunked down on a heated agitated specialty system.

    But of course, there's problems. Since that crap eats away copper almost exclusively at the edges, the etching proceeds from the outside of the board toward the middle. Consequently, the traces in the middle of my boards look fan-freakin-tastic; perfect. But the traces along the outside 1/2" of my boards look pretty bad. Luckily, the outside of my board is mostly ground planes and high current stuff: big big traces. My workplace has a good supply of know-how people (University physics research department), and one of the guy's in the electronics shop said I could probably reflow solder to patch the small holes, and lay down a few pieces of copper wire to hold solder in the bigger bare patches. I tried it, and it worked pretty well.

    So granted, its more time consuming and tedious, but hell for 4 bucks, that's that much more money I can spend on my amplifier components and speakers. Keep it in mind if you're going for first time board making.
     
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