For the most part I agree with what howmus said, I just want to add a few lessons I've learned along the way:
I started life as an audio technician back in late 60s /early 70s (my first paying job was assembling Heathkits, for those those that remember them). Rosin core solder was developed for the electronics industry to solder components (resisters, diode, etc.) to circuit boards where you need very little solder/flux, but for anything bigger you must use external flux; paste or liquid, it cleans the oxidation and pre-wets the surface so the solder won't bead up and helps the solder to flow, (just like ballasting track, you pre-wet the ballast with alcohol or detergent/water so the glue won't bead up).
I was also taught in electronics school never to use more heat than the job requires, a 25 w iron for circuit board work, 40w for up to 18g-16g wire (or up to code 100 rail), 100w or more for wire larger than 16g and always flux and pre-tin wires. Copper wire and brass should be tinned, surfaces that are nicklesilver (like rail) or nicklesilver plated do not need to be pre-tinned, nor do they need any other pre-treatment such as cleaning with a wire brush or alcohol (unless they are visibly dirty), the flux will do all the cleaning that is needed to make a good joint. You can be generous with the flux, but don't forget to clean all solder joins with a toothbrush and alcohol after soldering is completeted as paint won't stick well to it well.
Care & Maintenance of soldering tips. This is probably the most important part of making good solder joins. The last half inch or so of the tip should always be shiny silver, if there is any discoloration or blackening (carbon crud) it needs to be cleaned. A damp sponge will usually be enough between joins, but periodically the tip should be cleaned with tip cleaner which is available for Radio Shack and other places. It's sorta like soap for your soldering iron, you just stick the tip in it and let the "soap" melt, give the iron/tip a few twists and then wipe the tip off with the damp sponge. Add some solder to the tip and dip in the cleaner again and rewipe with the sponge and you should have a like "new" tinned tip ready to go. If you tip gets black a lot, it's time to replace it. I generally like copper tips over iron plated tips because they transfer heat better and I like to shape them to a dullish pointed tip, but they do need to be cleaned more often.
One last tip: After pre-tinning a feeder wire, I put a little "L" bend in it at the end and about a half inch down I bend it in a bit of a zig zag shape, then insert it in the hole and lay the "L" against the rail. The zig zag bend creates enough friction in the hole to keep the wire from falling through, eliminating the need for that "third hand".
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
The flux that is in the solder just isn't enough flux, if you pre-load the tip (which is what I do) then the flux that was in the solder has already evaporated and burned up, so you need to add the flux at the joint.
"I don't understand why the hot solder hitting the rail and flux would not create a good joint due to the fact that the solder has sat on the iron for several seconds and is already heated well beyond its melting point. When the ball of molten solder leaves the iron and flows into the flux on the rail, it should carry enough heat to heat the rail to a very hot temperature long enough to make a good connection."
It should. Once you touch the rail with the iron, you still need to keep it there for a second or two so the rail can get up to the same temp as the solder for the join to complete. Even if you pre-load the tip you may still have to add more solder at the joint. If you didn't get enough solder on the joint the first try, let it completely cool off before reheating and adding more solder.
I use Radio Shack .022 diameter (62/36/2) rosin core Silver-Bearing solder. There's a little silver in it to make it stronger and it will not corrode over time. It's made for electronic circuitry, but it works great on track and just about anything else. The thin diameter heats up quickly and gives you more control, (you don't end up with big blobs where you don't want them)
Another tip on stabilizing the wire so you don't need the "third" hand, after inserting the wire thru the hole in the benchwork if the zig zag bend doesn't work just wedge something in the hole to keep the wire from moving.
Here's my process:
Add a little dollup of flux where I want it and then position the wire against the rail so I'm all ready to solder. I extend about 3 or 4 inches of solder from the roll, give the iron a wipe on the sponge and then touch the solder to it, feeding about 1/4" to 1/2" (of the solder wire) to the tip (the pre-load), enough to get the join started, (but you don't want a big blob on the iron). Position the solder right up by the joint (but not touching) and then bring in the iron and touch the joint, as the flux starts to sizzle (about a second) feed about 1/2' of solder into the joint right where the iron is touching the joint, pull the solder away keep the iron on there for another second or so and pull it away. You should be able to do it on a count of four. One (touch with the iron), Two (add solder), Three (remove solder), Four (remove iron), total time about 2.5 - 3 seconds. (My quantity (in inches) of solder is based on the .022, if you use .032 use a little less). Practice this with the count and you should get the hang of it, oh yeah, start the count once the iron touches, not before. For practice, pull a couple of inches of ties off the track, do the routine several times with just the counting, don't worry about the actual time, it'll get faster as you get the hang of it, after about a dozen times you should be doing it in about 2-3 seconds, then try it on a section with ties. Good Luck.
You can fix cold joints easily. First make sure the wire isn't going to move when you melt the solder, then add a dab of flux, wet the iron with some solder just as you would for a new joint and then touch the joint for a couple of seconds (about a 3 count) and remove the heat. The join should look nice and shiny, if it isn't, let it cool completely, before you give it another try or you will melt the ties.
Forget about the flux in the solder, there's only enough to get the solder to flow onto the iron or for tiny joins like circuit board work, for everything else you add flux, liquid flux (like TIX brand) works well too and is less messy. Flux (rosin flux that is) won't hurt anything, but it should be cleaned from the join after soldering as paint won't stick to it, (if you're going to paint your rails), a brush and some alcohol will do it.
The paddle tips are best suited for soldering wires together (splices).
To the poster who only solders the wire drops to rail joiners, you will still end up relying on the friction fit of the rail joiner to make and keep the electrical contact, over time time you may not find that to be so reliable as the joiners can work themselves loose because of heat and humidity. The point is that long term, rail joiners should only be relied upon for the mechanical connection, not the electrical. A better way if you want to completely hide the drops is solder them to the bottom of the rails before you lay them.
Sorry about my lengthy and overlapping posts, Jay.
I went to the RS site and did not see anything about flux in the solder. When I have used the same solder I dipped it in a little RS flux before soldering. Since the solder is in paste form, I put the iron tip in the flux and melt a little into a puddle. I have some RS liquid rosin flux but they stopped selling it.
IMPORTANT, practice with scrap track/wire. Remember, new does not always mean clean and ready for soldering when it comes to track or copper PC boards unless the PC board was already plated with a solder film. Develop a technique that gives you the results you want.
I use a Scratch Brush from Micro Marks to clean a spot of the track for soldering.
Anyone tells you soldering is easy, they have been doing it for sometime. Also applys to those who tell you that you do not need all the stuff I mention.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
The Tip Tinner and Cleaner you got is the right stuff, thats what I use, It used to come in a can about twice that size, anyway, I stick it right to the top of my soldering station, (there's foam tape on the bottom of the can). Tinner/Cleaner is essential for good soldering.
Don't stick the the iron in the flux, that'll start to build up crud on the tip. Instead, to start a soldering session, let the iron get hot, (with code 55 rail try setting 4), then dip the tip in the Tinner/Cleaner, (the stuff is hard like soap), let the tip melt it's way to the bottom of the can and give it a couple of twists and wipe it off on the sponge, melt a pretty good glob of solder on it and put it back in the Tinner/Cleaner, twisting it again and then wipe off the extra solder with the sponge. If the solder is evenly distributed around the tip and nice and shiny, your tip is properly tinned and cleaned, if not repeat the process. As you use the iron, areas on the tip will start to show black and/or the solder beads up on the tip instead of flowing on, it's time for a quick dip in the cleaner and a wipe on the sponge. Allways wipe the tip on the damp sponge before and after each solder joint.
Forget about flux in the solder, as long as it doesn't say Acid Core. What RS sells is all electronics solder, so it is either rosin core or solid core (no flux, we apply the flux to the work anyway, so it doesn't need to be in the solder). both of which are fine for our purposes. You only have to be concerned about the core when you buy solder at hardware stores where they sell both rosin (for electrical) and acid (for plumbing), so don't buy solder in the plumbing department!
I used to be a certified solder instructor for the US Army at a rather large Army base. Around 1996, the Government, in its inifinite wisdom, closed the four DOD Solder certification schools. So, it's been a while since I taught soldering, but I have continued to provide advice and support to various US Army Programs for assembly and soldering of electronic equipment that the Army purchases for our valiant troops.
I have provided that little bit of my background so that you'll know that I know what I'm talking about. It's sad to me when I see this topic come up in a forum because the people that respond are genuinely trying to be helpful, but so many times, they don't know what they're talking about. It's not that they're doing anything intentionally wrong; it's just that they have never been taught and so one never knows what to believe when reading the responses.
So, let me give you my 2 cents worth:
1) You do not need three hands to solder. What you need is to properly set up your work. If you're right-handed, your right hand will hold the solder iron and your left hand will hold the solder wire (and vice versa if you're left-handed). Set up the two pieces you're wanting to solder together so that they do not move in relation to each other. You can use any type of vice or clamp that you have available. For example, when I splice wires together, typically one of the wires is already attached to a part, but the other wire is not - it's hanging free. So, strip the wires and form two U-hooks so that they 'hold hands' with each other, and then use a clamp or some other method to hold the free wire. The key here is to put the 'free' wire under tension so that the wires don't move when you touch them with the solder iron.
Let me try to describe how I prepare a feeder wire. After drilling a hole in the roadbed, insert the wire from underneath and strip the wire.(After playing with this for a while, you'll figure out about how much insulation to strip off.) Make two 90 degree bends in perpendicular planes in the wire. Coming up vertically through the roadbed, the wire should make a 90 degree turn toward the rail (this covers the distance from the hole to the rail) and then make another 90 degree turn parallel to the rail (this is the part of the wire that gets soldered to the rail.) It just so happens that 22 ga solid wire almost perfectly fits the web of Code 83 HO rail. I found that after getting it in position, I can slightly push the wire up from underneath while holding it against the rail with flat-nosed pliers so that it stays put and doesn't move when I get ready to touch it with the solder iron.
2) ALWAYS make sure that the two metal pieces being soldered are clean! For feeders, I always clean the web of the rail with the wire brush head of a Dremel tool. I never re-use old wire. New wire is generally pretty good and solderable.
3) The amount of flux contained in rosin-cored solder wire is usually all you need - especially if your pieces are clean and solderable (see #2 above). The only purpose flux serves is to prevent the two metal pieces you're soldering from oxidizing during soldering. That oxidation is what will prevent good wetting action, and good wetting is indicative of a strong solder bond. Extra flux will never overcome dirty parts. I usually only use (extra) liquid flux when I'm reflowing a bad connection or wanting to completely remove solder from a connection, such as during disassembly of soldered parts.
4) Heat Control. This is another area of great misunderstanding. So, I will try to describe everything that you must consider:
a) Use a tip that is the correct size for the parts being soldered. A tip that is too large for your work will only lead to overheating and damage. Conversely, a tip that is too small will never get anything hot enough.
b) Set the solder iron to the proper temperature. What's the proper temperature? It's whatever gets the solder flowing without overheating, so you'll just have to try different settings on different parts to find out what works best for you. My rule of thumb is to solder small parts at a setting of 650 deg F, medium parts at 700 deg F, and larger parts at 750 deg F.
c) You are correct that the sponge provided with your iron is there to clean the tip. Here's what you should be doing. Wet the sponge with cool (not cold!) tap water and then wring it out so that it is damp (not wet!) to the touch. When you're ready to solder, wipe the tip on the sponge and the tip should be a bright silver color. Don't wait too long, because the tip will turn brown from oxidation and you'll have to re-tin it.
d) Place your solder iron so that the tip makes contact with both pieces being soldered at the same time. If one piece is larger than the other, (such as a rail vs. a feeder wire) then place the flat blade of the tip against the rail, while at the same time making contact to the wire with just the tip of the iron. That will transfer more of the heat to the rail. The key to controlling the heat is to make sure BOTH parts are heating up simultaneously. Once you have placed your solder iron against the two parts, DO NOT move it. Leave it in that spot for the entire process.
e) Next, (THIS IS THE IMPORTANT STEP) you need to form what we in the industry call "The Heat Bridge". Place the solder wire at the junction of the rail, the wire, and the iron tip. The idea here is to get the solder flowing. It may take a second or two or five, so be patient. Once the solder starts flowing to both parts, then you know the parts are hot enough. When the solder starts flowing, immediately move the solder away from the iron tip. You can now 'paint' the connection with solder to get it in between all portions of the connection. Also, the liquid solder will flow back towards the iron tip, since solder always flows towards the heat source. This helps the solder go where it needs to.
f) When you see that solder has flowed into all the crevices of the connection, remove the solder wire FIRST. Once the solder wire has been removed, THEN remove the solder iron from the connection. Try not to move any part of the connection as you remove the iron or after removing the iron. The solder will remaind liquid for a few seconds until it cools, and if anything moves, the conncetion could be damaged.
g) Last step. Before turning the iron off, protect the tip by touching the solder wire to the tip so that a small bead of solder remains on the tip after it has cooled down. So the next time you turn the iron on, the bead will be there and can be wiped off at your next attempt at soldering.
I hope this short tutorial has helped!
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Something to consider also is the mechanical connection between the soldering tip and the barrel of the iron. I have two different types, one the tip screws into the barrel and one uses a small screw to retain the tip. Before plugging in the iron, I always either back off the screw in tip and retighten or loosen the screw and rotate the tip. This assures a good "bond" for heat transfer from the heating element to the soldering tip.