Solder

Rosin core

My current favorite solder of

My current favorite solder of choice is Multi-core 63/37, 0.032" diameter, 2% C502 no-clean flux. 

Lead-free solders have a higher melting point and are often a little trickier to work with.  I personally just stick with good ol' 63/37 or 60/40 leaded solder.  Just don't eat the solder or your workpiece and there's no danger.  Washing your hands after working with solder is usually a good idea as well.

The one thing I use in addition is a liquid flux on track.  I use Superior's SuperSafe 30 on track joints before soldering them.  It's an amazing flux that's safe for electronics work, and really makes those rail joints go together fast and clean.  I've found if I depend on the solder flux, it takes longer (risking melting some ties) and doesn't wet the joint nearly as well.  I just clean it off with a warm water and baking soda solution to prevent any residual corrosion issues, but even joints I've not cleaned never seem to show issue.

Should mention I'm an N-scaler myself, but I work on HO and O scale layouts with the same stuff.

Nathan

to be sure

Use only rosin core solder. Most come in 60/40 tin/led content. Get the thinnest solder available. The thinner the better. For track work get a rosin flux paste and after cleaning, coat the joint before soldering. You will get a better join that way. Clean the Track rails, at the join with alcohol before and after soldering. Before ,for a better join, after, to remove the flux.

Buy your solder at an electronics store, not at a home improvement store. This way you are sure to get the right type of solder.  

Your Soldering iron should be about 35 to 50 watts with a pencil point tip.

Flux

Hi all

I also need to solder the feeders to the rails.  I have a roll of 60/40 rosin core solder .032 diam that I got at Radio Shack.  I see above that there is one vote for liquid flux and one vote for paste flux.

My question - since I have never done any soldering before - since the solder contains flux is flux a necessity or is it just good insurance for a good solder joint?

if it is a necessity - are there more votes either way liquid vs paste?  I called my local RS and he is out of flux of any kind and had no idea when more would be in.  So if Lowes has some would it be ok to use.  The only soldering I plan to do is feeders to rails and just maybe the feeders to the buss wires.

Flux

If you are a: using a 60:40 or 70:30 rosin core solder, and b: clean the area to be soldered with a brass brush or fine sandpaper, and c: tin the pieces before soldering two things together, you can get away without using additional flux.   Tinning is the process of adding a small amount of solder, which helps you to form a better bond when the pieces are joined.

My neighborhood Do-It-Best hardware store has a couple of choices in solder and flux and carries soldering irons. Ace has a similar selection.

If I was doing feeders, I would tin the feeder wire and carefully clean the rail where I wanted to make the joint. Place the wire against the rail, feed in a tiny amount of solder, then touch the iron to the work until the solder gets shiny and flows.  Let it cool for a minute or so and then give it the tug test.

Much more than you need to know is at http://en.wikipedia.org/wiki/Flux_%28metallurgy%29

Optional

Good insurance. Makes nicer solder flow for better wetting of the surface. Wouldn't solder rail joiners without it however. No way to clean the inside of the joiner.

Printed circuit boards and other electrical circuit soldering is done without additional flux proving it is not mandatory.

Joe is spot on - brush or sand the area to be soldered. Cleanliness is next to Godliness when soldering.

 "since the solder contains

I never use flux when soldering feeder wires to rails or buss. As long as the rails are new and clean shouldn't be a problem, just make sure you have electrical flux cored solder and not solid plumbing type.  If the rails are dirty or weathered you should clean them to bare metal at the feeder location using a wire brush or what ever works in the spot then I'd probably add a bit of paste flux as insurance. If the joint is going to work without flux you'll know in a few seconds, it will flow smooth to both parts and a bit beyond, if it balls up and doesn't flow stop and clean it better then try again. Practice is the best approach, solder some practice wire to scraps of flextrack to get a feel for how much heat it can stand without melting , etc. ....DaveB

Thank you

Thank you for the input.  Hopefully I won't burn the house down.  

Thank You All

Just placed an order with McMaster-Carr for some solder and flux and a needle applicator.  Thanks to all for their educational and informative input.