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tinning

Discussion in 'General Electronics Discussion' started by SparkyCal, Jul 22, 2020.

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  1. SparkyCal

    SparkyCal

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    Mar 11, 2020
    Is it advisesble to tin every connection before you solder? Or is it just an unnecessary step. If there is an advantage, what product would you recommend
     
  2. Martaine2005

    Martaine2005

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    I personally tin every connection and then solder.
    Obviously through hole PCBs are the exception.
    There are other things that I don’t tin, but I can’t think what they are at the moment.
    For me, tinning makes it easier and quicker to solder.
    Others may have differing opinions but that’s how I do it.

    Martin
     
  3. Bluejets

    Bluejets

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    Oct 5, 2014
    Same here.... as for which product...if you are talking of the simple wire tinning, then same solder as one uses on the pc board.

    There are other forms of what is referred to as tinning on bus bars or heavy bare copper conductors.
    This usually takes the form of a paste where the bar is warmed and the paste applied and then wiped clean of excess.
    Wouldn't see to much of that in hobby electronics though.;);)
     
  4. shrtrnd

    shrtrnd

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    Solder flux (liquid) helps solder flow and adhere to the connections well, however it can get messy and I always clean the
    excess solder flux from my work using isopropyl alcohol after I do the soldering.
    I use a block of sal ammoniac to re-tin the soldering iron tip when it needs it, because gunk build-up on the tip interferes
    with heat transfer from the tip to the components being soldered.
     
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    YES

    No it isnt


    Yes, makes for a better, faster joint


    The same rosin cored solder that you are going to make the joint with
     
  6. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    Perhaps the attached PDF's will help.

    Bertus
     

    Attached Files:

  7. Kiwi

    Kiwi

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    Jan 28, 2013
    Depends on the actual joint you are making.
    At work I do a lot of wire to wire joints, so twist the untinned wires together before soldering.
    Also wrapping wires around terminal posts, or through a securing hole on some terminals, is best done without tinning.
    Tinning before soldering to circuit board pads is definitely required.
     
  8. Audioguru

    Audioguru

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    Sep 24, 2016
    I tin stranded wire to hold together the strands.
    My soldering iron is temperature controlled and is always at the correct temperature. Cheap soldering irons, even ones with a light dimmer circuit get too hot which incinerates the rosin in the solder. I always use Name-Brand solder not the cheap junk from over there.

    I never use bare copper wire that has turned green with corrosion, Instead I use clean new wire that is already tinned.
     
    hevans1944 likes this.
  9. hevans1944

    hevans1944 Hop - AC8NS

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    Jun 21, 2012
    For prototyping work, especially when wiring components inserted in a solderless breadboard, I use a spool of tinned copper wire, 24 AWG, that is inserted into cut-to-length pieces from a spool of Teflon tubing, sized for a sliding fit over the wire. These two items, a spool of wire and spool of tubing, were acquired many years ago at a local surplus electronics store (Mendelson's) where everything was originally sold by weight. I got a very good price for the wire and the tubing, so I purchased a "life time" supply.

    By using bare, tinned, wire with a separately applied insulating sleeve, it is very easy to construct point-to-point wiring. You unspool some of the wire, estimating the length of wire you will need, and either solder the end of the wire to the first attachment point or insert it into the breadboard contact. Route the wire to the second attachment point, bending if necessary. Finally, you cut the bare wire from the spool, leaving an inch or two of excess, or less if you have acquired some experience. Then you eyeball the length of tubing you need to cover the wire between the two points of attachment, cut that length from the roll of tubing, slide the cut piece over the wire, and either solder the free end of the wire to the second point of attachment or insert it into the breadboard contact.

    Having the wire and the insulation as separate pieces avoids the necessity of stripping the wire on each end and possibly nicking the wire. A nicked wire will soon break at the nick, even if you solder over the damaged area. Teflon insulating tubing may seem like a luxury... and it is. Were it not for the fact that I acquired a large spool of it several decades ago, I would be using another form of insulation over my bare, tinned, 24 AWG copper buss wire.

    Somewhere in my pile of junque I had a roll of tubular green fabric insulation, sized IIRC for 20 AWG. I often used this until acquiring the Teflon. It was just the right size to fit over one-watt carbon composition resistor leads, and "back in the day" when we built circuits on bakelite boards with swaged terminal posts to hold components, it was perfect for that task. I also discovered that I could strip the insulation from some types of stranded wire, up to about a foot or so of insulation, and use that to cover 24 AWG solid tinned copper wire. Sometimes Teflon insulated wire was available, but it required a sharp single-edge razor blade to cut the insulation from the underlying wire. This was how I found out that Teflon tubing was very good insulation, but it was years later that I found it for sale at Mendelson's, way back in their "wire" department on the third floor. BTW, riding that creaky old freight elevator up and down to the third floor was all part of the ambiance and experience of visiting Mendelson's on a rainy Saturday morning.

    @Audioguru mentioned that he never uses bare copper wire that has turned green with corrosion. Good advice that, but sometimes lengths of four-conductor telephone cable "became available" with red, green, black, and yellow insulation over bare copper wire. You had to separate out individual conductors, cut them to the required length, then strip and tin the ends to make your prototype connections. Freshly stripped ends on insulated solid bare copper wire will generally tin well with a quality rosin flux-core 60/40 solder and a clean soldering iron at the proper temperature. I have a one pound spool (lifetime supply) of Kester Alloy Sn63Pb37 that has a Flux "44" Rosin Core in a 0.040" diameter solder shell, manufactured 16 July 1992. This is a eutectic alloy that melts and solidifies at a specific temperature without going through a "plastic" and granular phase transition. Highly recommended over any other solder, especially for beginners just learning how to make good solder joints.

    Avoid ANY solder claiming to be "lead free" unless you really know what you are doing. Plumbers joining copper pipe for potable water use, and amateur radio enthusiasts, use lead-free solder. Hams sometimes use a solder with silver in the alloy to improve the conductivity of copper carrying large radio-frequency currents. I don't have any experience with this yet, but I am building a hexagonal-shaped copper-loop antenna and will be going back over the joints with a silver-based alloy solder. Radio frequencies are conducted only near the surface because of "skin effect," so I need to make sure the surface of the joints is at least as conductive as the bare copper pipe. I could also silver-plate the copper pipe, but that would be rather expensive and may not be necessary if the antenna works "as is." It pays not to overthink things like this before actual field trials.
     
  10. dave9

    dave9

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    Mar 5, 2017
    The question is too vague, like writing "every connection", but not mentioning whether that only means wires.

    If it doesn't mean wires, I never pre-tin new components. Old components, if they are scavenged/salvaged, they are already tinned from their former life in a product. New Old Stock components, often I can just wipe them with a dry paper towel to abrade away a slight oxidative film (not to be done on very ESD sensitive parts).

    When I do feel the need to tin first, I stick the component lead, or wire, in a tin (container not metal) of flux, then if I have some leftover solder blobs (whenever I have some solder scatter, I throw them in a little box the solder spool came in, tape at the bottom so they don't fall out, lol), then I'll take the soldering iron, melt a solder blob onto it, and stick the fluxed lead or wire into that.

    Ultimately the answer is, do you find you need to do it for certain joints to improve them? And is it worth the bother to spend that extra time instead of just flowing some flux onto the area you're soldering first, which often makes as much sense but either way you have a plan how to deal with the particular soldering situation.

    A bottle of rosin flux/alcohol solution with a precise applicator tip is liquid gold for easy soldering and using less solder because you aren't depending on the flux in the solder and then using more solder than really needed just to get enough flux. I see that happening far, far too often when people start out soldering, massive overkill amounts of solder because they needed more flux to help them along, and/or they used a cheap non-temperature regulated iron that burnt up the flux too quickly, or an iron with a poor tip so they were just melting more and more solder without it flowing.

    As far as what product I'd recommend, get a cheap chinese tin of rosin flux, and a precise applicator bottle. You can buy the bottles but I just reuse eyedrop bottles. Mix alcohol with it to achieve a thick liquid, but thin enough that your choice of bottle, allows you to dispense a precise amount based on a controllable amount of pressure on the bottle. This assumes that if you can't tolerate residue, that your project can tolerate an alcohol rinse to get rid of any excess flux.

    Really it is take it on a case by case basis, not some rule about always or never. It's definitely easier to start out not using extra flux, then add it if you aren't getting the flow you need, when needed. It often isn't needed. You'll know those situations when you see them based on past results.

    So I sort of took the topic sideways, in that pre-tinning is really just about whether you have good flow and plating, and adding flux separate from the solder can solve that.
     
    Last edited: Jul 27, 2020
  11. bertus

    bertus Moderator

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    Nov 8, 2019
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I should offer to do a translation into Australian.
     
    bertus likes this.
  13. roughshawd

    roughshawd

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    Jul 13, 2020
    I use lots of flux. I find that most of todays components are either coated in some kind of plastic, or are just generally "dirty" as what could be impure or badly manufactured from low quality materials... there are alot of aluminum components that just don't solder well(or at all).
    So if I was to give some advice as to the type of flux to use. You can use any kind, just use plenty of it. I have more problems without flux than I do with flux, and the heavily fluxed joints work hold so much tighter that I don't want to change... choose the best you can get.
     
  14. dave9

    dave9

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    Mar 5, 2017
    ^ While I am an advocate of adding flux if there's any chance it'll matter, I have not seen any instances where components have a plastic coating or are dirty, unless it's some old surplus parts. Even parts I cannibalized myself from gear destined for scrap will have a solder plating on them already, from their previous installation.

    Aluminum? I have no idea what you're referring to, I never see any aluminum besides heatsinks, and never any attempt to solder to them. Do we have a language barrier or ??? I wonder if you have a very bad supplier and are dealing with counterfeit parts?
     
    Martaine2005 likes this.
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