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OT removing layer before soldering

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  • #16
    If the insulation is rubber then the copper should be tinned otherwise the copper will be attacked by sulphur from the rubber - well it was when I worked in the cable making industry!
    Last edited by ptjw7uk; 06-30-2020, 06:03 PM. Reason: spelling
    I have tools I don't know how to use!!

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    • #17
      The copper is tinned- I assume what's happening is that I'm electrolytically removing tin oxide. The 3 minute test didn't remove the tin- and I don't care if it stays or not. I probably do want it to stay- but be solderable like it normally is. I didn't expect the electrolysis to work as well as it did, but of course I'm happy that it did. Solder will now flow all around each strand, and will fill the junction, which is how it normally works.

      What I'm calling tin oxide is probably some dirty compound with sulphur and other contaminants, so probably not true to call it tin oxide. The water sure got dirty quickly.
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #18
        Have you seen this
        https://www.instructables.com/id/How...es-in-minutes/
        I have tools I don't know how to use!!

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        • #19
          So there it is- without electricity. I'm glad I experimented- it works well with just the baking soda solution with electricity, so salt and acids not needed. But that's a good ham trick. He was using concentrated solutions- mine were very dilute. I used just a pinch of salt in perhaps 2 oz of water, same with the baking soda. I should try a concentrated solution of baking soda with current. I get a good result in literally 5 seconds, though the surface of the wires doesn't look shiny afterwards. Shiny would be even better.

          I played with this a bit more, dipping the soldered ends to see what would happen. That made a black substance leach into the water. That would be lead I'd assume. The tinned wire didn't add any visible products to the water, though the water did get brownish. I wonder what difference using a different anode would make- instead of using the stainless cup as the anode-
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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          • #20
            And my sandpaper takes care of it, regardless of any chemistry involved. With money riding on the repairs, I could not afford to risk later corrosion.
            Paul A.
            SE Texas

            Make it fit.
            You can't win and there IS a penalty for trying!

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            • #21
              High quality soldering requires cleanliness so the classes in same teach the use of an eraser (pink, white or if needed - abrasive) and scrub the wire then clean with alcohol. Then solder with flux and clean with alcohol after cooling.
              Glenn Bird

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              • #22
                Why do find it necessary to solder a low-voltage test or Comm. coaxial cable? Perhaps the manufacturers intention was that person's use crimp terminations?
                Last edited by reggie_obe; 07-01-2020, 04:46 PM.

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                • #23
                  Solder naked, one less layer.

                  Do not post pictures however.

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                  • #24
                    Ok, now I understand. It's the cotton T-shirt getting in the way-
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                    • #25
                      Crimp connections are used in many cases. I have personally made thousands of crimp connections. There are also displacement style connectors where the wires, usually with the insulation still on them, are forced into a notch which pierces the insulation and into the copper conductor. I have also used this style of connection many thousand times. And then there are good old, screw terminals. And yes, thousands of those too.

                      The cables are mostly not intended for any particular style of termination. Yes, they are made with both stranded and solid wire. They are made with tinned and bare copper. And these factors are influenced by the type of connector that is used. But this is not absolute.

                      The connectors are generally intended for one type of joint or another. A connector that is made for soldering is generally only used with solder. One made for a crimp connection, likewise is normally only crimped. Etc. Screw terminals can be used with bare wire, tinned wire, and with crimp connectors on the wire.

                      My first choice was always the crimp connection. Generally, speaking and with the proper tools, it is the fastest and most reliable method. But the proper tooling can be expensive and for some situations crimp connections are not available. And if the wrong tools are used, a crimp joint can be a real problem. Soldering is more labor intensive and can fail if not done correctly. I have seen more than one cold soldered joint in connectors. Often a silver plated or other type of connector was stored for long enough for oxide to develop on the solder terminals and the flux did not do it's job. The connection looked good, but was not. It can take a good eye to spot all such problems.

                      However, when done properly, a solder joint is probably the best in terms of low resistance and reliability.

                      And of course, almost all of our electric wiring in our homes and commercial buildings is done with some form of screw terminals. And our lights usually work just fine.

                      All these methods have their uses and all can be the "best" solution.



                      Originally posted by reggie_obe View Post
                      Why do find it necessary to solder a low-voltage test or Comm. coaxial cable? Perhaps the manufacturers intention was that person's use crimp terminations?
                      Paul A.
                      SE Texas

                      Make it fit.
                      You can't win and there IS a penalty for trying!

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                      • #26
                        I want to see a video of Paul sanding 20 or more tiny wires in a strand to get them clean.,

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                        • #27
                          At one point I did a lot of car stereo installations. I hated the crimp connectors, and I still do. Today just proved my point once more- I was modifying an ac circuit and came across a crimp connecting some ground wires together. It was loose- I could almost unscrew it by hand off the wires. A marrette would have been better, but that's my opinion. Some places have put marrettes in a bad light, and banned the use of them.

                          House wiring is one thing, and it's seldom if ever called for to solder any connections. With stranded wire- well it sure is handy that heat shrink tubing came along. Twist, solder, lay the soldered part parallel with the wire, shrink on the insulation- or as I often do if soldering isn't going to happen, I twist, then fold the twisted part in half, then lay it parallel and use shrink. If there's no shrink I use electrical tape, but then use a zip tie over the end of the tape. I'd trust my life to that long before I'd trust a crimp. But that's just me.
                          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                          • #28
                            Originally posted by darryl View Post
                            ...That made a black substance leach into the water. That would be lead I'd assume....
                            Most lead compounds are extremely insoluble in water. If they are formed I would expect to see them show up on the electrodes or as a sediment. I suspect your black substance is not lead. Could it be some compound of sulfur?

                            metalmagpie

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                            • #29
                              The patch cords are all made, and the sound system in the pub is hooked up and operational. I'm not completely happy with it, though it does sound good- now I'm looking for a transformer to power the sub crossover with phase adjustment circuit I found. For some reason all these little transformers I have either have too little voltage, or too much voltage. I don't want to spend half my day, plus gas costs to drive to a supplier, only to pay too much for one little transformer- but I probably will spend two days taking a transformer apart and rewinding the secondary-
                              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                              • #30
                                Which is what I'm doing right now. I chose a transformer which does not have weld beads across the laminations, took it apart all the way, removed all of the secondaries except for one layer. Counted the turns, removed a few to get a nice round number of turns left. That turns out to be 40 turns- slipped all the laminations back in and tested it. 4.2 volts ac- and I need 14 plus 14 volts, or 28 volts with a center tap. So- 280 turns to put on now. Glad I have a winding jig with a turns counter.

                                What I'd really like to do is find several transformers with the same size Es and Is, and set up to rewind them all while I'm set up for it. Many times I need the same secondary voltages, and every time I look through my rag tag stock I don't find anything suitable. Most of the time I don't touch the primary winding, so that relaxes things quite a bit. It's time-consuming, but this is more of a hobby for me now so I can justify it. All that magnet wire I've been latching onto over the years is coming in handy.

                                Last edited by darryl; 07-02-2020, 06:35 PM.
                                I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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