On Sat, 25 May 2013 07:08:54 -0400, "Tom" wrote:

Hi Gentlemen,
I have the two capacitors for the bottom matching coil on the Diamond X200a.
I have sanded and cleaned the old solder off the sleeve there that looks
like chromed brass.

I have tried a couple times so far to get the solder to stick to that brass.
I have tried some plumbing solder, some plumber's paste (acid flux) I
cleaned it, sanded it, filed it and it wont stick to that brass ring part at
the bottom. I tried 50/50 solder, rosin core, lead free, and another couple
types I am not sure their breakdown but they are electronic solder. Any
ideas or tips to try to get that solder to stick? I see it has a nylon
insert there of some sort. I am wondering if I am getting it hot enough, I
think I am, I am using a 250 watts gun solder type solder iron. Any ideas?
Thanks

Your soldering gun tip isn't staying hot enough to solder anything
with a large thermal mass. Using 63/37 lead/tin solder, you need a
large chisel tip on either a thermostatically controlled soldering
iron that will get you up to about 200C. If you have a propane torch
with a copper soldering tip (used by plumbers), that will also work.
The soldering gun isn't going to work because the copper "wire" tip
doesn't have enough mass. As soon as the small tip, touches the large
brass heat sink, the temperature of the tip will drop drastically.
It's also not themostatically controlled, so you don't know what
temperature it's running. Too cold and it doesn't solder. To hot and
you vaporize the flux and produce oxidized dross. You need a tip that
will get hot, and stay hot at the correct temperature. Don't bother
trying with RoHS solder. You might try practicing with an old brass
coax connector before attacking the antenna.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558