Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Where to hire someone to build circuit? - Moderated

  1. Mar 31, 2013 #1
    Where to hire someone to build circuit? -- Moderated

    Well, here's the deal. Thanks to help from someone on this forum, I have successfully built the circuit to drive a police lightbar (for filming a movie) that I want using the parts I want and keeping it super cheap. I've come to a new problem. Soldering circuit together for me seems to be a touch out of my skillset. I get really frustrated when I spend a few hours soldering a circuit together and it doesn't work. I also just learned that if you solder a transistor to a board, you kill the transistor. Super-fun! That should be on the package somewhere.

    I digress. I've been looking for a place on the interweb to find someone who would be willing to build the circuits for me. Can anyone on this forum point me to a place or is willing to give me an estimate on how much it would cost? See if such a thing fits into my budget to frustration ratio.

    Thanks!
     
  2. jcsd
  3. Mar 31, 2013 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    I've soldered several transistors by hand in my day, and all survived the operation. Are you sure you weren't rubbing your feet on dry carpet while you were working?
     
  4. Mar 31, 2013 #3
    No, but they're not mosfet, there just cheap old BC547, they shouldn't be static sensitive. The ones in my breadboard have been through a lot more and they still work. I'm building a circuit with a 556 and two transistors and the 556 part works as it should.
     
  5. Mar 31, 2013 #4
    In the interest of full disclosure, my transistors (2 of 8 I've soldered) are actually fine. For some unknown reason, the circuit I soldered has decided to start working magically on its own. I would still like to know if some hobbiest is interested in getting paid to do it....
     
  6. Mar 31, 2013 #5

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    What were you using to solder with?

    For electronics you need a small iron, not a soldering gun..
    And small solder - .040 or smaller. My favorite is Kester 44.

    Freddy get some small wire like inside telephone extension wire and practice.

    A little 'soldering flux' makes the solder flow better.
    You must gently heat the work and apply solder opposite from the iron. Solder follows heat.

    Your 'sometimes it works sometimes it doesn't' sounds like looseness.
    That happens when you drop a glob of molten solder on a joint and just hope it sticks. What you get is not a solder joint but a shrink fit that's intermittent.

    Practice with small wire until you get the feel for just how much heat it takes to make solder "wet" the work and flow up it toward the iron. You can see it walk right up the wire.

    Leave transistor leads a bit on the long side. If soldering them to a massive joint grasp the lead with an alligator clip for a heatsink .

    I had a summer job as a solderer. They made us spend an entire day practicing how to solder D-plugs without melting the insulation on the wire.

    If I can do it you certainly can.

    http://www.hometheatershack.com/for...strated-diy-guide-making-your-own-cables.html
     
    Last edited: Mar 31, 2013
  7. Mar 31, 2013 #6

    berkeman

    User Avatar

    Staff: Mentor

    For the record, solicitations are not allowed here on the PF. That said, I think we should help you to try to figure out what went wrong when you tried to solder your project up yourself. I'm okay with members contacting you via PM to offer to help you directly, but there is benefit to the general EE forum if you can post what problems you had in soldering up the circuit yourself.
     
  8. Mar 31, 2013 #7
    Oops... Sorry about my post. I was really looking for a direction to go and not necessarily a person from here to do it, but I understand how it breaches solicitation.

    Thank you Jim Hardy for all the advice. I learned most things you stated from my dad when I was a kid and use .032 solder and an iron with a pointy clean tip although I need a new tip and usually do glob solder onto a joint. I will try what you said about putting the iron on one side and the solder on the other. Sounds like that will help a lot.

    When I mentioned 'sometimes it works' it is not so much a bad solder joint but an incorrect connection. For instance in this mentioned circuit I have a PC mount potentiometer that spans about 1/2" I soldered all my connections to the three pads on the two pin side not noticing that I left the far leg (the important one) of the trimmer un connected. Without that the 555 wasn't working at all.. Hehe. But thank you for the vote of confidence!!
     
  9. Mar 31, 2013 #8

    vk6kro

    User Avatar
    Science Advisor

    There are problems with using resistors, even if you just bought them.

    Firstly they may not be the correct value. Some of the color coding makes red, orange and brown just look like different shades of brown. So get a digital multimeter and check them.

    Next, the wires will usually have oxidised and will not accept solder. So get a razor blade or a sharp knife and make sure the wire is very clean and shiny.

    Use solder that has flux built into it and a soldering iron that heats up the joint in a couple of seconds. You should be able to see the molten solder flow to all parts of the joint. If it just stays in one place in a spherical blob, then the joint isn't clean enough.
     
  10. Mar 31, 2013 #9

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    and they're so small these days its hard to tell which end you read the color code from.

    (not to mention I cant even see the stripes anymore)
     
  11. Apr 1, 2013 #10
    I would try a local Vocational HS - with an electronics program - I am sure they would love the experience to make something real - and the instructor should know good solder technique.
     
  12. Apr 1, 2013 #11

    AlephZero

    User Avatar
    Science Advisor
    Homework Helper

    The components you buy are made to stand the heat of being soldered to circuit boards using mass-production machines, which effectively "swipe" the whole board across a wave of molten solder to make all the joints at once. That gives the components a much hotter time than a hand soldering iron.

    If you are "frying" components by hand soldering, the most likely reason is that you are using the wrong sort of tools, or the wrong method.

    Here's a video of how to do it right:
    https://www.youtube.com/watch?v=QL86gO9mfT8
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Where to hire someone to build circuit? - Moderated
Loading...