You know, I have enjoyed building my LT-40, I really have, but everything is a project. I decided to convert it to a taildragger, because I won't be flying any time soon (read snow again in Virginia). Well, I go to attach a spring to my line, and I cannot for the life of me get the solder to stick to the spring or the line. Do I have to go buy some flux to put on it so I can get the solder to stick? My solder has rosin core, which is doing NOTHING.. HELP!!

What wattage is your iron.
If it is above 30-45 watts then get some paste solder

It's 30-35, shoudl I still use paste?

Yes, you are going to loose a lot of heat and if there is any oxidation on the metal, the flux is needed.

You'll need an acid flux to solder steel, rosin won't work. Lightly sand the spring (or rod) with 220 grit and clean with alcohol. A 200+ watt iron works best for me.

Stick,
A hotter wattage iron is good, but you can solder 2-56 rod with a regular soldering iron if it is properly fluxed!

Well I went to Radio Shack today and bought Flux Core solder (they had no traditional flux) and liquid solder, and neither of them work. NOTHING will stick to this kevlar cable crap that came with this 2-56 system. So what am I supposed to do? Not put springs inline to take some load off the servo? I am so disgusted..