Model Railroading > What type of solder?

Was wondering what solder mix is the best for attaching copper wire to nickel silver track?...I got some rosin core lead/tin stuff but it doesn't stick to the nickel silver well...Help!...Thanks

Rosin core 60/40 should work fine. The key to successful soldering is to ensure both surfaces are completely clean. Any contamination ie. grease,oil,dirt,oil from your fingers, etc will not allow the proper bonding by the solder. Also the tip of the soldering iron needs to occasionaly be filed to ensure that the maximum amount of its face is in contact with the surfaces being soldered. You'll find that over time the tip becomes dimpled. After you've cleaned the surfaces mechanically (files,sandpaper,etc)I would swab the areas with alcohol right before soldering. Good Luck!!~~~Ed

One thing I have used that has really helped my soldering is the use of flux.

The last two comments are completely correct.As one who has spent 30 yrs in the electronic dist. business, that's the right way to do it.

Using non acid flux(only) works fine!

One aditional thing besides the good comments is make sure both items that need to be soldered are hot and about equal temperature.

I agree with all of the above. Only thing I can add is an article that you might want to read.
http://members.home.net/sask.rail/construction/lsbuild/soldering.html
-trainman-

A couple of more words of advice. Having the rail clean is most important; I file nickle silver rail with a jewelers file at the spot I am going to solder. 2nd, although it seems backward, use a high wattage iron to solder rail. This heats the rail faster and helps avoid melting plastic ties.
Also, with regard to filing iron tips: If you have a cheap all copper tip, then filing will give you a new flat surface, but if you have a higher quality tip it will be iron clad, and then filing will only remove the iron cladding and ruin the tip. (Please don't ask how I know!) Iron clad tips should only be whiped on a wet sponge while hot to remove oxidation and then retinned with solder.

If you are soldering to factory weathered rail, be sure file off the weathering in the area you are soldering.

To have a good solder joint, you need -

Both surfaces must be clean, as many on this thread have pointed out.

Both surfaces must be fluxed - rosin core flux is what you want.
There are other fluxes, but they're for special uses.

You need the right solder. 6/40 tin/lead solder sold for electrical
work is fine.

Both surfaces must be above the melting point of the solder.
Solder only sticks to metal when it's hotter than the melting
point of the solder.
The way to get the surfaces hot enough without melting the plastic
ties is to dump heat in fast. That way it gets very hot in a small
area. When you've finished soldering the heat will spread out, but
since there's not a lot of it, it doesn't get the whole show very hot.

Keys to doing this -
Use a large enough soldering iron. I use a 45 Watt iron or a 140 watt gun.
Have a flat surface on the iron - a chisel shaped point is usually
best. You want as much area as you can get to be in contact with the joint.
Put the solder and the soldering iron both on the joint. Don't try to mash down the solder with the iron. That only heats the solder.
Keep the tip of the iron clean. The advice about iron clad tips and copper clad tips is good.

You can't move the wire or the rail when the joint is cooling. If at all possible, try to have the wire already mechanically held in place before soldering - for example, by propping the wire against the rail and holding it with a weight.

If your solder joint is lumpy or dull colored it's a "cold joint". Reheat it. It should be shiny.