Soldering electronic components.

Discussion in 'Hints & Tips' started by Keith M, Mar 5, 2017.

  1. Keith M

    Keith M Staff Member Moderator

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    I guess it's always seemed obvious to me since I've been playing about with various electronic components since I was about 12 years old and got my hands on some of the early transistors, but I've just realised that many modellers who have perhaps never previously come into contact with any form of electronics apart from maybe switching the TV on, might not understand that for almost all electronic components, heat is the enemy, and will quickly destroy pretty much all solid state devices if overdone. There's me spouting on about soldering LED's, decoders, etc. and suddenly it dawned on me that for the uninformed, it all seems so easy until a few seconds of extra heat from a soldering iron (NO pokers heated on the gas ring please!!!), and bang goes another bit of kit. I must stress that for any electronics soldering, a 15 to 20 watt soldering iron with no more than a 3mm bit should be the maximum used, making the joint as quickly as possible, particularly heat sensitive devices may need a heat shunt, which could be nothing more complicated than gripping the joint with tweezers or fine needle nosed pliers immediately after removing the soldering iron from the joint, thus conducting the heat away from the delicate component. I don't recommend using your fingers as a heat shunt though! If you first 'tin' the two parts to be joined together, and allow to cool slightly, melting the two parts together will be much quicker and therefore less chance of heat transfer where you don't want it. If you are a 'first time' soldering iron user, then I suggest you first practice just soldering a few wires together until you get the hang of it before moving on to more expensive items, but remember, 'carrying' solder on the iron to the joint is NOT the right way to do it, tin each first, then apply the iron just enough to get the solder on each component to melt together, then remove the iron, but keep the joint still until cooled so that you don't get a 'cold joint', where the solder has been moved whilst cooling, as this can cause poor conductive joints. There really is no "Black Art" to soldering, but it is "Practice makes perfect".
    Keith.
     
  2. Ron

    Ron Full Member

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    Just ordered a new 20w soldering iron as I have some LED's and resistors to solder and my 60w iron is a bit to big!!:)Thanks for that Keith:)
     
  3. paul_l

    paul_l Staff Member Administrator

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    Great advice Keith

    Also use sockets as well, as these can normally take heat better than an IC chip, and will allow a chip to be replaced without using solder, and only cost a few pence.

    [​IMG]

    I have several weapons of choice I have aquired over the years

    For General modelling and layout work - track wiring etc, a Antex XS25 25W soldering iron with a chisel tip. Modified with a 5m mains cable - that cat chewed the original cable.

    Electronics and bench top kit making, a Maplins solder station 60W tempreture controlled, with interchangeable bits - both shape and size, also need different bits for whitemetal, lead free and lead based solders, as cross contamination can effect the joint.

    Heavy duty - e.g. soldering connections to batteries, an Weller 80W iron with 12mm chisel bit.

    Really Heavy duty - an old soldering iron with a 1 inch chisel bit - I could probably solder wires to full size sleepers

    Instant heat pistol gun - handy for releasing wires from components

    The last two rarely used.

    The advantage of a larger bit size, is it retains a lot of heat so when you try to solder to something made of a good heat conductor, it can provide enough heat to melt the solder without you having to dwell on the item to heat it up. In and out fast.

    Paul
     
  4. Keith M

    Keith M Staff Member Moderator

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    I've accumulated a fair selection of soldering equipment myself over the years, starting when I was 12 and Mum worked for part of the AEI group, so I got a "Henley Solon" 25watt iron via the Company shop. That's still working, along with 2 other 25watt ones, an "Antex" 18watt which is my 'Electronics' soldering iron, a recently bought battery powered 'Lidl cheapo', a "Weller cloned" 60watt soldering gun, and ready for my GT3 brass chassis project, a variable temperature 50watt 'soldering station' (sounds 'posh' don't it?). If all else fails then next step up is my butane blowtorch, normally only used for plumbing jobs, but could be brought into play if more heat is needed!:avatar:

    Keith.
     
  5. ianvolvo46

    ianvolvo46 Staff Member Moderator

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    Its a great thread gents.. now a section on the evils (or otherwise) of flux.

    Ian vt
     
  6. paul_l

    paul_l Staff Member Administrator

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    Bit like the smell of napalm in the morning.

    Horses for courses

    For electrical and brass work I use multicore lead based solder, with an additional tin of resin flux.

    A damp sponge works wonders for keeping the iron tip clean, followed by a quick dip in the flux and apply a small amount of solder to re-tin the bit.

    For whitemetal either Carr's Red or Ortho Phosphoric acid

    Carr's green label flux is also very popular.

    Note both the red label, green label and Ortho Phosphoric acid all need washing off after use as they will corrode the metals.

    Paul
     

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