Newbie questions about soldering...

Discussion in 'General Electronics Chat' started by sofakng, Nov 5, 2007.

  1. sofakng

    Thread Starter Member

    Oct 30, 2007
    19
    0
    I've soldered before but I was always terrible at it so I'm trying to learn how to "properly" solder. I've found a bunch of articles (and videos) online and I thought I was knew what I was doing, but...

    I bought a new cheapo RadioShack 15-watt soldering iron and holder (metal rings plus a sponge).

    According to what I've read, you should always keep solder on the tip to prevent oxidation and after soldering a joint you should wipe the tip on the sponge and then put new solder on the tip.

    I tried soldering a couple of joints (with my new iron) and then wiping it on the sponge but it made the solder on the iron cool down and the solder stayed on the iron. On top of that, it made my tip look all nasty!

    Here are my questions:

    1) Why does my iron look so nasty after soldering two joints? (Go here for a bunch of high-res pictures) Was I using my sponge incorrectly? This is a brand new soldering iron!

    2) How do I solder two wires together or how do I solder one wire to an LED? Do you twist the wires (or wire+LED) together? ...otherwise it seems like you need four arms (one to hold each wire close to each other, one to hold the solder, and one to hold the iron!)

    Thanks for any help!
     
  2. jpitz31

    Active Member

    Oct 24, 2007
    37
    0
    Check out the below links

    http://www.hackaday.com/2007/10/26/how-to-introduction-to-soldering/

    http://www.makezine.com/blog/archive/2007/01/soldering_tutor_1.html

    Yes, after you wipe your tip on the sponge your tip will cool a bit. Just let it heat up again. One of the reasons you always tin your tip is when the iron is hot it oxidizes. By tining the tip you reduce the oxidation process so the solder oxidizes and not your tip. Just keep wiping to keep it cleaned off.

    The application of tinning keeps the tip clean and helps with better heat transfer.

    Cheap solder irons are just that, cheap. You can pick up a temp controlled solder iron for around $50.00 Most of these irons provide better heat control and have a special coated tip to provide better tinning. Yes you will have to replace the tip every once in a while. If your tip is coated do not sand paper the tip as you will destroy the coating.

    Weller makes a tip cleaning stone that will clean up the tip without destroying the coating.

    Thanks

    Joe
     
  3. sofakng

    Thread Starter Member

    Oct 30, 2007
    19
    0
    Thanks for the reply.

    So are you saying my soldering iron looks normal then? (since it's a cheap one)

    I thought the point of wiping the tip onto the sponge was to clean the tip (and make it look new), but for me the solder doesn't even come off the tip...
     
  4. jpitz31

    Active Member

    Oct 24, 2007
    37
    0
    Yes, Your tip is normal.

    Even the expensive iron tip's will oxidize and look this way.

    Yes on the cleaning, but your goal is to put solder on the tip so that the tip is clean and coated with solder, "know as the process of tinning". You always want a nice thin coat of solder on the tip. But to keep it shinny you will need to wipe it often and reapply the tin every so often.

    Thanks

    Joe
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    A home-built temperature control can be made from a lighting dimmer and a duplex outlet. Including 4-square box, cord, NM clamp, wire-nuts, mudring, and cover, this should run less than 10 bucks. I splurged on a fifty cent night-light as well - makes an "on" indicator.

    Tips are available separately from many places. A high-grade tip is an inexpensive upgrade for a low-cost iron. I have also ground custom tips from stainless steel screws, but I do not endorse this practice.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    With only 15 watts to play with, I would guess that a temp control is like a new bumper on a Ford Falcon. That iron is going to have a hard time heating a pad and 1/2 watt resistor lead enough to get a good joint. Good size for SMT work, though.

    Knew a guy who had a gold plated tip on his iron. You wanted to be careful not to abrade the gold, but any amount of crud just wiped right off. Fantastic heat transfer, of course.
     
  7. chesart1

    Senior Member

    Jan 23, 2006
    269
    1
    If possible, mount the led first on the unit first and then with the led mounted you can solder the wires to it. I would twist the wire around the led lead once and then solder it. As you know, only apply enough solder to coat the connection. A little practice goes a long ways. When you are done, there should be no pin holes in the soldered connection and you should still be able to identify both leads in the solder.
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Regarding "four hands..." there are affordable gizmo-thingies called "third hand" which are quite, um, handy.:cool: They have a moderately heavy base, a couple of alligator clips, and a magnifier. You can find them online, or at gem & mineral shows, some gun shows, or at Harbor Freight.
     
  9. Sauve

    New Member

    Nov 16, 2007
    4
    0
  10. RiJoRI

    Well-Known Member

    Aug 15, 2007
    536
    26
    My favorite "third hand" is a pair of needle-nosed pliers, with a rubber band wrapped around the handles.
    If I'm lazy or in a rush, I twist the resistor's and LED's legs like a twist-tie holding a bread bag closed. Otherwise, I cross the two legs, and wrap one leg around the other -- if I recollect, this is called a pig's tail.

    --Rich
     
  11. jdcruz

    New Member

    Nov 27, 2007
    3
    0
    I'd recommend using one of those adjustable mechanical holders that can be clamped on the edge of your work desk. Put the solid component you want to solder a wire on into the jig and you should be good to go from there.
     
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