17 Sec Timer-Fabrication

Discussion in 'The Projects Forum' started by Oxbo Rene, Mar 8, 2009.

  1. Oxbo Rene

    Thread Starter Active Member

    Feb 20, 2009
    Good morning;
    Thought I'd show you the pictures of the little timer Bernard and I messed with for so long. Actually, I cut it short, just to be able to move forward again, etc. Works like a charm.
    The circuit on the breadboard is the actual circuit I was working with, put together the little perf-board model cause I still want to work with Bernard's new pulse clipper circuit he refined, etc.
    Also, anyone know where I can order a PCB kit <$20.00 ? Radio shack doesn't carry them any more and the ones I find on the net are beyond my budget, etc.
    Have a nice day,
    Last edited: Mar 8, 2009
  2. Wendy


    Mar 24, 2008
    Are you wanting to make a PCB? If so, hand drawn, toner transfer, or photographic?
  3. SgtWookie


    Jul 17, 2007
    If you want to replicate the contents of the Radio Shack PCB etching kit, you can pay Marlin P. Jones & Associate's website a visit:
    They sell dry ferric chloride powder; you have to mix it with water in a plastic or glass bottle.
    Their copper clad boards aren't absurdly priced, either:
    You could use their DATAK resist pens, or a Sharpie (I haven't had wonderful results with a Sharpie) or try the laser toner transfer method that Tom Goot's website talks about:

    Tom's method uses a mix of hydrogen peroxide and muriatic (dilute hydrochloric) acid as etchant; both should be readily available to you locally at drugstores (hydrogen peroxide) and pool supply (muriatic acid) stores. Be careful with the muriatic acid; it's fumes are very hazardous to breathe, and it will permanently etch many surfaces (even concrete) moments after being spilled upon them. If you're going to go the muriatic/peroxide route, use it outside, keep a bucket or two of water handy, and use a fan to blow the fumes away.

    For roughing up the PCB's prior to applying resist, you can use green 3M Scotchbrite(tm) pads, available at most grocery stores. Don't use steel wool or sandpaper, as steel wool/sandpaper will become embedded in the soft copper and cause problems later.

    Isopropyl alcohol works well as a solvent for Sharpies and rosin flux, and is very useful for cleaning PCB's before and after soldering. 70% has too much water in it. I've found 93% isopropyl in my local Wal-Mart pharmacy; it works well and is pretty cheap. Don't leave it exposed to air, as it will absorb moisture; it is also flammable, and burns with a nearly invisible flame.
  4. Oxbo Rene

    Thread Starter Active Member

    Feb 20, 2009
    Why yes !
    MPJA is where I bought my breadboard, probably a month ago (trashed my old one for one with built-in Pwr Supply).
    Have their catalog right here.
    Don't know why I didn't think of looking in it LOL.
    I like laying out a board as opposed to using the perf-board, is aggravating trying to navigate the little holes, etc.
    Bill, I use the little press-on stencils (probably can't find them anymore either).
    Please understand, it's been 10 yrs since I did the mailbox thing, and probably another 10 yrs since I did any circuit experimentation (made my switching pwr supply), etc.....
    Tx's so much.
    Last edited: Mar 8, 2009