How can I solder a wire onto a piece of metal?

Question

I am replacing the antenna on my radio. I removed the old antenna to find that a wire had been soldered directly onto the bottom of the antenna. I attempted to solder the wire onto the new antenna but could not get the solder to stick to the wire or the antenna.

Just bought a soldering iron just to do this and have no experience so any tips would be appreciated. I think that one issue I may have is that I am using solder that is too thick. Going to try picking up some thinner solder later this week to try with.

Answer 1

Steven's answer describes fairly standard soldering in a device. You're trying to affix a piece of wire to an antenna, which is basically a big metal rod. In all likelihood, your soldering iron can't produce the heat necessary to warm part of the antenna up to where solder will melt. There is just too much mass in the antenna, and too much surface area. This is more like soldering pipe. Some options:

1) You could step up your game with a soldering gun. That'll pour out the heat. Directions are basically as Steven describes at that point, except you'll want to spend a lot more time putting heat into the antenna than the wire.

or

2) Just connect the two mechanically. Depending on the size of the antenna, you could do anything from holding the wire on with a hose clamp, to using one of those grounding wire to cold water pipe connectory things.

I assume this is just a consumer radio receiver; if so, anything that gets you the reception you want is good enough.

Answer 2

Soldering electrical connections is not difficult but there a couple of things you need to know.

First, you need a soldering iron that gets hot enough (but not too hot) for the conductor you are trying to solder. You also need to use a resin solder (not the same solder you'd use for plumbing). All of the surfaces need to be clean; if there is any oxidation it will not "stick". You can clean copper surfaces with steel wool.

If you're using a new soldering iron, you have to tin the tip. To do this, heat up the soldering iron and touch the solder to the tip of the iron so that you cover the tip in a thin layer of solder. Wipe the excess off with a damp paper towel or sponge.

Now, heat both the conductor you are trying to solder and the pad you are trying to solder to. When it is hot enough, touching the solder to the pad (don't touch it to the iron) should cause the solder to melt and flow into the connection. If it doesn't, it's not hot enough. Once the solder is sucked into the connection, remove the soldering iron and let the connection cool. You should be able to pull the wire with a bit of force. If it pulls away easily, you have a bad solder and will need to try again.