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Soldering gold-fill


#1

I just joined the forum and am really looking forward to learning
from all the experts here! My first question is about soldering
gold-filled wire. I have had some success in the past but the links I
soldered today are off in their color. The solder is gold as it
should be and the rest of the jump ring looks copper in color. I’m
guessing that the heat brought the copper in the gold layer up to the
surface. Am I on the right track? It doesn’t appear to be the brass
from underneath the gold but I could be wrong. I made a quick attempt
at cleaning one up with the flexshaft but it did not appear to change
the color of the metal. Below is step by step how I soldered the
rings, which may give some clues as to what happened and what I can
do to get the metal back to gold toned.

I dipped each ring in Luxi Flux and let them dry. Then I brushed on
Batterns at the joint. Since the rings are quite small it pretty
much ended up flooding the piece. This may have washed off the Luxi
Flux but I can’t be sure. I dipped my pallion of 14K easy solder in
the Batterns and then balled it up. I heated the ring, applied the
solder ball and then typically had to help it cover the joint by
dragging it around with my pick. The whole thing ends up darkened in
parts. I quenched and then soaked in pickle for a while. There were
still stains so I made up a super pickle and left them in there for a
while. After rinsing them, I tried a little steel wool to see if that
would remove any of the remaining stains and improve the color.
Things cleaned up well but I’m still left with a gold toned solder
area and the rest a bit copper in color.

Many thanks for reading my very detailed description. I would be SO
excited to learn what I did wrong so I can either re-do these rings
or restore them to the proper gold tone.

Thanks so much!
Anne


#2

Hello Anne,

GOOD question! I rarely solder GF, so will be interested to hear
from others who have more experience. Here are my comments.

Soldering gold-fill is fiddly. Too much heat for too long equals
color change. You mention using easy gold solder; I use extra-easy
solder. The less time the metal is heated, the better. Any time I
work on gold, I dip into an alcohol and borax mix, and flame it off.
Repeat until the metal looks lightly ‘frosted’, then Battern’s flux
on the joint before soldering the joint. Also, a very small flame
directed to the joint reduces heat exposure.

Judy in Kansas, where record-breaking warm temps are on for today!!
Just a taste of spring.


#3

I suspect you may be burning off the relatively thin gold coating
and leaving only the base metal behind. I know gold (not gold filled)
is more expensive, but better in the long run.

Janet


#4

Thank you Judy and Janet!

I bought a gold testing kit and determined that I had "burned off"
the gold layer, or rather it melded with the core and was no longer
on the surface where it’s supposed to be!

I attempted to make the jump rings again yesterday, this time using
an oxi-acetylene torch with a small tip, and was still not happy with
the results. The #6 tip on the Smith Little Torch was just too big so
I will have to try again with a tiny tip (#0) to see if I can direct
the heat solely on the joint. The problem is that these rings are
quite small - I wrapped them around a # 6.5 Pepe dowel. I’m guessing
that it is going to be nearly impossible to get the solder to flow
without overheating the rest of the piece. I will give it one more
try with the smaller tip and see what happens. I am also going to get
some paste solder to see if that will flow better/faster than my
regular 14k solder. I will also get some Cupronil, as I read some
recommendations that some prefer it to Batterns.

If this doesn’t work, I will have determined that it’s just not
recommended to solder small pieces in gold fill. I had no trouble
soldering 12 gauge bangles or larger jump rings. The project I’m
working on is a gift so I will just go ahead and buy 10k or 14k and
be done with it!

Thanks for your help!
Anne


#5

Unfortunately I have never had any success soldering fill, and
finally gaveup. When feasible I use 14K gold. On large pieces, I
just resort tocold connections, such as rivets. Can only do this if
it is compatible with the design of the piece, but at least I get a
chance to use up the gold fill that I have on hand. Alma


#6

Hi Anne

I work primarily with sterling silver and I have not worked with
gold fill.

But I do a lot of work with paste solder.

Your idea of using paste solder to get the solder to flow faster is
a good one.

Paste solder melts a lot faster than sheet or wire because the
solder in the paste is very finely ground, as small as 100 or 200
micron in some solders.

You still have to get the parent material and the solder up to the
solder flow/melting point, but it should happen much faster with
paste.

Good Luck
Regards
Milt
Calgary Canada


#7
The #6 tip on the Smith Little Torch was just too big so I will
have to try again with a tiny tip (#0) to see if I can direct the
heat solely on the joint. The problem is that these rings are quite
small - I wrapped them around a # 6.5 Pepe dowel. I'm guessing that
it is going to be nearly impossible to get the solder to flow
without overheating the rest of the piece. 

The number 0 tip is likely too small. Even with oxy acetylene, a #0
is difficult to light. You don’t often need a flame around a
millimeter or two long(pretty much pinhead sized), which is about
what that tip will give you. try a #2 or #3, and adjust for a
suitably small flame, with suitably low regulator pressure settings.
But the problem is likely not really your torch size, but the oxy
acetylene itself. That’s a very hot flame when adjusted right. Use
less oxy than you normally would so the flame has a bit of yellow
still to it. very soft and reducing. That will help with getting the
metal too hot and damaging the gold layer. And then the real problem
with things getting too hot, isn’t even the torch. It’s how hot you
need it to get to melt your solder. What grade of solder are you
using? You should be using a very low temp gold solder. There are
gold solders made for gold fill. They equate to an extra easy low
karat (6K seems common with some of these), or perhaps 10 K grade.
Generally, they’ll be melting lower than your usual easy solders for
gold or silver. If you see the metal even glowing much, it’s too hot.
The idea with this type of metal, unlike solid gold and silver, is to
pretty much heat just the solder and joint, not the surrounding
metal. when the joint gets hot enough, the already hot solder will
flow in. And for the record, a 6.5 mm mandrel isn’t that small.
Small might be winding.4mm wire around a 1 mm or less mandrel. Those
sizes get a little more tricky… :slight_smile: But if you’re winding that same
small size wire (a quarter to a half millimter diameter wire), then
it’s the wire size that would make it “small”, not the mandrel. Like
in soldering gold, but unlike silver, with gold fill you only need to
be heating the joint itself. There’s no need for anything but the
joint area itself to be hot for the solder to flow correctly. In
fact, you really don’t want anything other than the joint itself to
get hot. So as you’ve already figured out, a smaller torch flame may
be better than a big one.

But what you do with it is more important than the flame size. Try
working with the flame glancing over the joint from a position above
the inside of the ring,(if the ring is flat/horizontal on a soldering
block, or a similar position if the ring is otherwise
held/positioned) with the flame heading then past/glancing over the
joint, and away from the ring. That way, the ring itself isn’t in the
flame or it’s backwash, at all. Just the joint.

Hope that helps
Peter


#8

I used to solder 20 gauge GF jump rings, using easy or easy repair
gold solder. They were more or less okay, if I did not over polish
them.

Mlou Brubaker


#9

First - Cupronil is not a flux, it is an oxide retardant, normally
used to prevent firescale in sterling silver.

Second - If you really want to join the rings, the small tig welders

  • PUK for an example, would work perfectly. someone around you
    probably has one.

The base metal inside the goldfill can be worked with one of the
older versions of tig welders (PUK2 or III) that are selling for
little money on ebay.

Third - the gold color solder available for nugold for example,
melts at a lower temperature and is a halfway decent color match for
brass and not too obvious for the goldfill. Not perfect however.

Fourth - you could pen plate the trashed area with gold - not
difficult and probably worth investing in if you are going to do a
lot of it.

Judy Hoch