Ralph Mowery wrote:
"Bob Eager" wrote in message
...
On Mon, 16 Aug 2010 18:43:08 +0100, john hamilton wrote:

I have to connect this AAA battery holder to a toy. Although I have a
small soldering iron, my soldering skills are poor. I can see myself
easily melting all the plastic around the contacts before I can get
anything to stick to the tabs.
To add to the other suggestions about soldering: if you can get/borrow a
temperature controlled iron, run it at a lower temperature and use 63/37
solder.


That is usually the wrong way to do the job he wants to do. Use a very hot
iron, hit the joint fast with a lot of heat and then get out quick. The
tabs will get hot very quick and melt the solder. If he applies a low heat,
the plastic will get a lot of heat on it before the tab gets hot enough to
melt the solder.

Overheated tips give me a hassle with oxidation. I think the most
important factor is thermal conductivity to the joint. The flow can be
slow with a small pencil-pointed iron. A bigger tip with a flat side
can work much faster.

I'd clean the iron, tab, and wire, make a good mechanical connection,
apply rosin flux to the connection and the iron, and turn on the iron.
When the flux smoked, I'd begin testing the iron by touching solder to
it. When it melted solder quickly, I'd touch the iron to the
connection. Almost instantly, the flat side of the tip and the drop of
molten solder should conduct enough heat to the joint for it to draw
solder from the iron. I'd have the iron out of there before the plastic
could soften.

Dadburnit, the last battery holders I bought had the tabs riveted to the
battery contacts. They develop resistance from invisible corrosion
around the rivets. I have to keep spraying with contact cleaner. I
also have jumper cables that develop resistance from unseen corrosion
where the wires are crimped.