The wire size is fine, but you are not going to believe this, you are melting the ties because your iron does not have enough reserve heat. Believe it or not, I use a 100 Watt iron with a fairly large tip, lots of heat reserve.
The idea is to get the heat to the spot you want to solder quickly and get the job done. This prevents too much heat from getting to the ties and melting them. Also, the size of the solder is a little big, I use no larger than .032 60/40 or 63/37 rosin core solder.
The final steps and probably the most important part of soldering is the surfaces to be soldered, in this case the wire and the rail must be CLEAN. Clean surfaces are 90% of a good solder joint. I generally clean the part of the rail I am going to solder with a wire brush in a Dremel tool. The next step is to flux the joint either with the flux used for doing copper plumbing (Nokorode), although you need to clean the finished joint with a cleaner such as Isopropyl Alcohol. The other alternative is to use one of the no-clean water soluble fluxes used for electronic assembly and repair. The last thing is to be sure the tip of the iron is clean and tinned to get maximum heat transfer to the joint.
Now comes the final step, making the joint. With the well tinned iron, hold the tip of the iron to the joint making contact with the rail and the feed wire. when the joint is hot enough, you can tell by watching the evaporation of the flux, apply a small amount of solder to the joint. If the joint is hot enough, the solder will flow into the joint immediately. Take the iron away and let the joint cool.
A little practice and you will be able to make perfect solder joints and not melt any ties.
For the last few inches of feeder I use figure 8 speaker wire (typically 14 x .020" I think). I cut and test-fit the length of track first, and then when I'm happy with it, I:
- lay the section down with the ties 'up';
- separate the plastic ties at a convenient point and then slide them along to open a gap of about 1 inch;
- file the bottom edge of the rail so it's nice and shiny;
- tin both the base of the rail and the both ends of the speaker wire;
- solder one lead from the speaker wire to the underside of each rail.
Then I turn the rail over, and drill a hole in the roadbed to correspond with the position of the feeder wire. I re-fit the rail section, poking the feeder wire through the hole, and sliding the ties back into position. Then I attach a screw terminal to the free end of the speaker wire, underneath the layout. Done properly, you can barely see the feeder once it is ballasted.
I also solder multiple rail sections together into one continuous section if possible. In this case I apply flux to both ends of rail, and also to the rail joiner before fitting it. I have successfully laid continuous sections of rail up to 9 feet long (ie 3 x lengths of N scale Peco flex track), but you need to be extra careful on curves.
I use rosin-core solder and a 40W iron and a long, fine, chisel tip. I've also used a 25W iron without problems.
You didn't mention using flux. It is important to keep the surfaces clean while the joint is being soldered. Flux prevents the corrosion while you solder. I use a 40 watt iron and NoCorrode flux (from a hardware store). Do not use acid flux. Let the iron get good an hot then make your joint.
I use about 22/24 solid wire for a short (3") drop to heavier (14ga.) under the layout.
Plain old 60/40 solder.
"nokorode" brand solder paste.
A CLEAN, HOT iron, well tinned. (I actually use a gun)
Dab a bit of the paste on both rail and wire.
Tin the wire
Hold the wire up against the rail, and just touch the joint for only a second or so. Do NOT add any more solder than what's already on the wire.
The secret is a HOT iron so you can work very quickly. Using too small an iron takes too long, giving the heat time to travel along the rail and melt the ties. That also means it takes longer for the joint to cool, leaving a weaker joint.
Excellent soldering advice! Far more items are 'melted' of 'fried' by trying to use too small an iron than one too large. SPEED is the answer, you need to transfer a LOT of heat quickly to make a good joint and not 'cook' everything nearby. This requires a large 'reserve' (stored) heat capacity, *AND* a good clean heat conduction path (NO dirt, burnt flux, carbon, oxidized solder, dirty metal, etc.).
And, you do NOT need a lot of "wattage" (power), but a substantial copper tip on the iron to STORE heat. I've found that a 37 - 50 watt iron is quite sufficient, WITH a large tip on it. Such is FAR more effective than a 100 watt iron with a small tip.
IF you get the metal clean, you will NOT need any flux other than the rosin in the solder. Additional liquid rosin flux is available from electronics suppliers.
I'd AVOID the use of any corrosive flux (ANY that contains Zinc Chloride, for one) whenever possible. This includes several that SAY they are 'non-corroding' ... I've seen the contrary result! A corrosive flux, in SMALL quantity, can be used if absolutely necessary when soldering OLD rail that is already in place and cannot be adequately cleaned by other means. One problem that can result from 'acid' fluxes (like zinc chloride) is that it soaks into wooden ties and roadbed and makes them somewhat conductive! This can short out 'detection' systems and give false indications, among other problems. I once worked on a model railroad where nearly a full amp of current leakage was being caused by this problem. The gentleman had LIBERALLY used a zinc chloride flux on ALL his rail joints and feeders. *BAD* idea!
And **NEVER** use a corrosive flux on WIRING ... not EVER!
Hmmmm. I don't know about N-scale track, but SOME current HO track is plated steel, and this can be hard to solder depending on WHAT the plating metal is. Common platings are Zinc and Cadmium ... both are near impossible to solder to, you have to remove (abrade) the plating at the solder joint.
There's even some plain steel HO rail floating about that's left over from W.W.II years. One guy here in town has quite a lot of it on his layout. Actually, that's NOT bad rail. It gives better traction than Nickel Silver rail, and 'wears' forever, but it does not work well in the presence of moisture ... it understandably rusts! It is also hard to solder easily (but it's not impossible by any means). It has higher electrical resistance than NS rail, but that's really NOT a big problem with adequate feeder wires.
And worst of all, I've even seen ALUMINUM HO rail. I suppose it could be used in display cases and such. Aluminum is impossible to solder to by any normal means. I have NO idea where that product came from ... perhaps a battery or wind-up train? It has several problems. It does not take kindly to being bent, it oxidizes and forms an insulating layer worse than brass, and it's near impossible to make a good electrical connection to it. Same problems as aluminum house wiring, but probably with lesser consequences! :-(
Fluxes CAUSE corrosion while you solder ... that one of their main purposes. What they prevent is OXIDATION, by corroding ('eating') the oxide layer away, and then keeping it away until the soldering is complete. They also aid heat transfer.
Rosin fluxes (liquid and paste) are only corrosive in their molten state, and are nearly inert when cooled and solidified. That's why they are safe for all but the most sensitive electronic applications.
Most all other fluxes (liquids and pastes) contain zinc chloride or various fluorine compounds. ALL such are BAD news for electrical soldering. Zinc chloride is PARTIALLY 'killed' hydrochloric acid. Zinc chloride REMAINS corrosive after the soldering is finished. It can cause problems, perhaps YEARS after the solder joint is made. NOT good! The zinc chloride can be PARTIALLY neutralized with baking soda solution. This kills the remaining 'acid', but the chlorine atoms remain, and can still cause problems. Fluorine causes similar problems. Once they're there, it's near impossible to totally remove them. Best to just AVOID such fluxes for all electrical applications.
My entire layout is Atlas code 100 flex, and I have feeders on just about every section. I used either 22 or 24 guage (don't remember offhand which it was) solid wire. This is how I've soldered both feeders and track joints, and using this method I haven't melted a tie yet:
My soldering iron of choice for feeders and track joints is a 25 watt Weller that I got for a few dollars at Home Depot. It came with a chisel tip that works great for this application.
I apply the iron on the opposite side of the rail from the feeder. The flat side of the tip should be parallel to the top of the rail, but the actual contact point should be the web of the rail with the iron held at 45 to 60 degrees off the horizontal. Think of web of the rail as the slot of a screw that you're inserting the screwdriver (chisel) tip into, but at an angle so it also contacts the head of the rail. You want as much contact area as possible.
I can't stress how important it is to keep the tip clean, well-shaped, and lightly tinned. I always have a damp cleaning sponge handy when I solder, and I clean and re-tin the tip after just about every joint or two. That seems like a lot, but it quickly becomes habit and doesn't take any more time in the long run because you aren't cursing and re-doing solder joints!
And oh yes, speaking of solder I always use .031 60/40 rosin-core for feeders and track joints. I've used both Radio Shack and Kester with good results. The brand doesn't seem to matter too much as long as it's halfway-decent electronic solder. No acid core or dollar-store stuff. And I've never used flux/paste/whatever for feeders or rail joints since I get excellent results using only the rosin-core solder.
"Trainman" wrote in news:XUcbc.5976$3 email@example.com:
This is the wellknow reflow method of soldering. When it's done right it works well. But when it's done wrong the result is a cold joint. I've found that it's best to pre-tin both the wire and the rail.
If you (the OP) is worried about melting ties you could just remove them. Cut off the plastic carrier and three ties around the point where you will be soldering. After you have attached the wires and placed the track you just slide the ties back under the rails. Use a little dab of glue to hold the ties in place.
I just recently did this on the club layout where I was drafted to rework some track. "Oh, nice soldering. You didn't even melt the ties" they said.