Soldering gold filled tubes

Hello everyone,

I’ve been searching through the archives, but I haven’t been able to
accomplish this. I’m trying to solder two square gold-filled tubes
at the ends. I’m using a yellow silver hard solder from rio grande
(recommended for gold filled). I apply a boric acid + denatured
alcohol solution, fire the piece until crystals appear, and then I
apply some handy flux (watered down). It’s very difficult to solder.
I find that I keep rotating the torch around the area that needs to
be soldered, but nothing happens. The goldfilled piece is starting to
change color, so I’m worried about it producing firescale before the
solder begins to flow.

Am I doing something wrong? Should the torch flame be large/small?
Do I need to heat the entire goldfilled piece with the torch, or
focus on one area? Can I do anything about the goldfilled piece after
it changes color to a slightly rosy gold color? Any advice would be
very appreciated.

Thanks in advance for your help!
Lana

I’ve always used gold solder for GF. Can’t speak for this particular
stuff but generally silver solders are touchier than gold solders.

Its possible your handiflux is watered down too much, I’m not sure
why you would water it down anyway.

Try cupronil…acts as both a firecoat and a flux. “A little dab’ll
do ya” (or is that trademark infringement?)