Soldering gun quetions

Discussion in 'FAQs' started by foulrift, Jul 15, 2008.

  1. foulrift

    foulrift Bob

    I just got finished reading some search posts on soldering guns and I still have a couple of questions.
    I have read where a lot of people use guns rated from 40w-140w.Many say that the 40w model is adequate enough for soldering both rail joiners and feeders.Others say that 140w is better because it get hotter faster.I'm looking for one that will do both,any suggestions?:confused:
    I have also read where many people prefer using a gun with a chisel tip as opposed to a pointed tip.I saw a gun in Big Lots with a pointed tip but are there other tips available? Any suggestions?:confused:
    Thanks for any help-Bobwall1
  2. ezdays

    ezdays Out AZ way

    First of all, we need to differentiate between a soldering gun and a soldering iron. A gun is a rather large gun-shaped device with a trigger and a heavy wire tip. The gun heats up quickly while you hold the trigger. These are bulky and difficult to control and provide more heat than you need. Wattages are in excess of 100 watts. An iron is a pencil-like thing with a solid tip and stays hot as long as you have it plugged in. This is probably what you're talking about. Tips vary in shape from a sharp point to a wide chisel and range from around 15 to 100 watts for electronic soldering. Recommendations for all-around rail and wire soldering on a layout might be a narrow chisel tip and about a 40 watt iron. Bigger is not better, higher wattages and hotter irons are also not better. Once you pick an iron, it's best to practice with it and get your soldering technique and skills down before you actually work on something you need.

    There are several tutorials on soldering and the various iron types and an article in a back issue of the Gauge emag on rail soldering, which is available on line here.
  3. foulrift

    foulrift Bob

    solderion irons

    Thanks Don-I was referring to a soldering iron-Thanks
    I a pencil type yesterday-40w with a sharp tip for $5-it is an off brand.Would this be a get what you pay for deal?Should I stick to a name brand?Also are the tips replaceable-if it comes with a sharp tip are there other tips available?
    Also as you suggest I plan to practice a lot before even going near the layout and that includes practicing soldering feeder wires both to the track and bus wires.
    Thanks again-Bob:thumb:
  4. nachoman

    nachoman Guest

    I use a 25 watt weller pencil type iron to solder code 70 rail. It works perfectly. For larger size rail, a 40-watt pencil type may be best. For wire soldering, I usually use the 25 watter.

  5. foulrift

    foulrift Bob

    Kevin-Thanks-What kind of tip do you use?From what you say I guess a 40w iron would be a good choice for both the track and feeders.-Bob
  6. ezdays

    ezdays Out AZ way

    I use a very fine point round tip, but only because I've been soldering with it for some 30 years and am use to it. I would recommend a narrow chisel point. For $5, you probably aren't going to get the best tip, and that's important. Also how you change the tip can be a hassle. I would suggest you spend a little bit more and get something that will last and enable you to change out the tip. You can then have different tips for different jobs if you want.
  7. RonP

    RonP Member of the WMRC

    I have one piece of advice with soldering. I remember all the times I did not do this and failed miserably.

    Pre-tin your wire.
    To do this you need to just put some solder on one of the wires before connecting them. This allows for a quick and good connection quickly when attaching one wire to a rail or what have you..
  8. railwaybob

    railwaybob Member

    You can pick up 25 watt and 40 watt soldering irons at places like Princess Auto for around $6 - $8 each. I have about half a dozen of them and they work very well for soldering rail joiners, soldering 20AWG track feeders to 16AWG track power busses (I use DCC). The trick for any soldering iron is to make sure it heats up to its maximum. If the solder melts immediately when touched to the tip of the iron, then it's hot.

    For ease of use, get a holder to hold the soldering iron in. The commercial ones are usually a large " coil spring-like" contraption that is screwed to a 4"x 6" metal base. The metal base has a depression to fit a small 2"x 3" sponge. Or, if you don't have something like that, then take a clean empty small tin, like a cat food tin, cut out a couple of notches so that the iron will fit on the top of the can but not roll off.

    Before you solder any rail joiners or pieces of wire, apply some flux to the joints - even though the solder may say it is "flux core" solder. There isn't enough flux in the centre of the solder to spread the flux on the work to be soldered. Flux comes in a paste form or a liquid form. Only a little bit of flux is required - a bit of paste on the end of a toothpick will do. Or, dip the ends of the wires into the paste. For liquid flux, a small micro-brush will do, or even that toothpick.

    Before applying the hot iron to the work to be soldered, wipe the tip of the iron off on a dampened sponge or a damp piece of cloth. As the iron continues to heat up, the tip of the iron will oxidize. You know the tip is cleaned off if you can see the silver of the solder. I presume you know how to tin a new soldering iron so I won't get into that here.

    With the flux applied to the parts, place your hot iron onto the parts to be soldered. Start counting - one thousand, two thousand, three thousand, four thousand. At the count of "one thousand", apply your solder. If the solder hasn't flowed into the joints/ wire at the end of "four thousand", immediately remove your soldering iron. The plastic ties on your rails (or the plastic sheathing on the wire) will start to melt.

    Keep your eye on the plastic ties. The minute they start to seem as if they are soft, immediately remove the soldering iron. Practice first on a piece of scrap track or wire.

    The key here is a hot iron, a clean iron, parts that have been fluxed. Apply the heat and the solder fast. Get in, get out, fast! Make sure the solder "flows". Solder that doesn't flow results in a "cold" joint that will cause electrical conductivity problems.

    Bob M.
  9. seanm

    seanm Member

    RailwayBob gave you great advice! One additional note. If you get flux, do not get acid based flux. If you get acid based flux you will need to do serious heavy cleanup after soldering. Rosin based flux (I refer paste) is what you need for general electronics work... now if you are building turnouts you might want to consider something stronger. but that is a whole other kettle of fish.
  10. ezdays

    ezdays Out AZ way

  11. foulrift

    foulrift Bob

    Don-That's what I thought-just needed to hear it from someone else.Spend a little more now and get something that will last.I'm assuming 40w will be OK for both rails and feeders?
    BobM and Sean Thanks for the advice.Bob-never soldered so how do you tin the iron?
    RonP-Thanks also for your reply.How is your layout progressing?
    All of you can be sure of one thing,I have no intention of soldering the layout track until I practice,practice practice!!!
    Thanks again Bob
  12. seanm

    seanm Member

    Tinning an iron is just placing some solder on the tip. You need to wipe the tip after almost every solder joint... at least I do. I use a soft lint free cloth like an piece of an old bed sheet. Heat the iron... wipe the tip..touch solder to the tip (make sure there is not a big blob... just some shiny solder) touch the items to solder and wait on sec.. touch solder to the heated area and wait a couple of seconds for a flow... remove the solder and iron.... repeat. Ofter you have done it a few times it is easy.

    One thing that has not been mentioned is the items need to be CLEAN before you solder. Dirty or weathered rail and such needs to be cleaned. I use a dremel with a wire brush to do this. When in doubt clean first.
  13. railwaybob

    railwaybob Member

    Every new iron comes with a copper tip or a plated tip with copper underneath. When the copper is heated, it oxidizes (forms a grey ash) and heat can't be transferred from the soldering iron to the solder and onto the parts that need to be soldered.

    So, the first thing to do with a new iron is to solder the copper tip. This is called "tinning". First, coat the tip of the iron with some flux - as seanm has mentioned, you will be using rosin-core solder an rosin-core flux. Never use acid-core solder, even on rails.

    Then plug in the soldering iron. Keep an eye on the copper tip. When the copper tip starts to smoke (the flux is starting to burn off), touch the solder to the tip of the iron. You want the solder to melt and flow all around the tip of the iron. Apply solder and concurrently twist and turn the soldering iron so that the solder flows all around the copper tip. You should end up with a shiny solder tip. Depending on the size of the soldering iron, this may be anywheres from 1/8" to ¼" from the tip of the soldering iron.

    With each use and application of the soldering iron, the tip of the iron will oxidize (a grey ash). This ash needs to be wiped off the tip of the iron before the iron is applied to the work. This is where that wet sponge or damp cloth comes into play. The sequence of events is this. Flux the parts to be soldered. Wipe the tip of the soldering iron on the damp cloth/ sponge. Touch the solder to the iron so that a bit of solder is on the tip of the iron. This solder acts as a heat transfer between the soldering iron and the parts being soldered. Apply the soldering iron to the part(s) to be soldered. Apply the solder to the parts (not to the iron!). Let the solder flow into the joint. Remove the soldering iron. Let the parts cool down on their own.

    Sometimes, when the solder is applied to the work, the solder may not flow from the iron to the work. This may require touching the solder to the tip of the iron to start the solder flowing. However, it's important that the solder flow into the parts and not onto the soldering iron and then into the parts. This is how "cold joints" are created which could cause some headaches down the road when the connection doesn't function properly. Always remember that you want the solder flowing INTO the parts.

    Periodically, the tip of the soldering iron will require some "dressing up" - ie reshaping. There is a natural acid in the solder, in the flux, in the parts being soldered, and even in the plastic insulation on wires. That's what the "grey ash" reaction is all about - the copper tip is being worn away by this acid chemical reaction. It's perfectly normal. This can "pock" the tip of the iron, reduce the tinned area of the tip of the iron, and generally reduce the effectiveness of the soldering iron. Take a file and file the copper tip of the iron into shape. (Not recommended but I've even used my bench grinder to reshape the copper tip of a soldering iron!) Repeat the tinning process described above as if it was a new soldering iron.

    This reshaping/ retinning process is usually for 20 - 40 watt soldering irons that have a ¼" diameter copper tip. If your soldering iron is one of those Weller-type irons with the small 1/8" tips, you can usually buy new tips for a couple of dollars at your favourite electronics store. You can also buy different shaped tips to do different types of soldering jobs.

    If you are using a soldering gun (the ones that resemble a space-age gun) that blasts out 100 - 140 watts, you may have to replace the tip. Replacements are usually available at your electronics store.

    Wherever electricity is involved (eg model railroading), you always want to use rosin-core solder and flux. Acid-core solder and flux should only be used on copper plumbing.

    Bob M.

    PS - If you have stores like Princess Auto (only in Canada), you can pick up 20 - 40 watt soldering irons for about $6-$8 each and 100-140 watt soldering guns for about $20.
  14. foulrift

    foulrift Bob

    soldering irons

    Thanks again guys.Some really great info and tips.I appreciate it a lot.As I mentioned before it looks like 40w should do the job for both rails and feeders.
    Thanks again-Bob
  15. Relic

    Relic Member

    I didn't read every word, so this may have been mentioned already,but,heat sinks,I use large 'gator clips,with some practice you can solder your joiners without removing any ties{before or after you melt them}
  16. foulrift

    foulrift Bob

    Relic-Thanks-Maybe you can answer this question-can I get away with using a 40w iron for soldering both the joiners and feeder wires?Thanks-Bob

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