Why my solder does not flow

Jewelry Discussion
1

I’m really hoping someone can shed some light on why my solder does
not flow. I am new to soldering but have been increasing my success
rate over the last 3 weeks. As of two days ago no matter what I do
the solder will not flow. It gets hot and goes a bright orange but
does not go any further. I pickle the piece first and make sure there
are no gaps in the join before I begin; I’m using the same type of
flame, same bezel wire; the same solder; I heat up slowly the whole
piece before I concentrate on the join and this was working for me
every time until two days ago. I would be really grateful if somebody
could point out what I am doing wrong. Many thanks

Linda, Leicester UK

2

Linda,

I am fairly new at silver soldering, but have many years at soft
soldering. The rules I have been taught have been 1. Make sure your
metal has clean shiny metal exposed (make sure you have neutralized
the pickle with baking soda and water bath. Buff with 0000 steel
wool.) 2. Flux the clean metals well, (flux chemically cleans the
surface and helps in heat transfer). 3. Get all surfaces to soldering
temperature equally.

So far in my limited experience with silver soldering I have not
heard of anyone pickling the metal prior to soldering. I do know that
if there is pickle on the metal and one tries to solder it the area
contaminated with pickle usually will not accept solder. (Been there
done that)

I hope I have help in some manner,

Ken Moore
www.kenworx.com

3

Hi Linda,

To solder successfully it helps to understand how it works. Soldering
refers to the process whereby pieces of metal are joined by melting
another metal (the solder) so that it wets the joint and holds it
securely when it freezes. That’s basically it, but there are a few
"gotcha’s".

The important word is wets. It’s just like water. Put a nice
clean pipe in water and freeze it; it’s then difficult to get the
pipe out, but use an oily pipe and it’s much easier. The
difference is that the water wetted the clean pipe, but couldn’t
wet the oily one. If the pipe wasn’t oily but dirty, the effect
would be the same. Solder works in exactly the same way. So all you
have to do is make sure the joint is nice and clean and you’ll get
a good joint, right? Well, no, it’s a little more complicated than
that, but not a lot.

To melt the solder you have to heat it up. The trouble is that the
very act of heating it also makes it dirty. The oxygen in the air is
only too eager to oxidise everything it touches, and, as far as
solder is concerned, metal oxide is dirt. Most metals oxidise rather
slowly at room temperature, but heat them up and the effect is very
rapid " so rapid as to make soldering impossible, unless you prevent
the oxygen from reaching the hot joint.

There are only three ways to do this: solder in a vacuum, solder in
an atmosphere devoid of oxygen, or coat the joint with an oxygen
barrier that can stand the heat. The first two options are rather
impractical, but the third is fine; the barrier is called a flux.
The job of the flux is to cover the joint with a barrier to stop the
oxygen from oxidising it. Resin is a good flux for soft solders and
borax for hard. If the joint and the solder are nice and clean then
these fluxes work rather well, but that’s all they do; they are
known as inactive fluxes. If the joint is a little dirty these
simple fluxes do nothing except act as a barrier, but there are
others that can do a small amount of cleaning too. Baker’s Fluid
is one such active flux for soft solder and EasyFlo is one for hard
solder. (I use a product called Auflux, which is a sort-of luminous
green liquid. It is used straight from the bottle and doesn’t froth
up as much as the powdered fluxes.) The active fluxes are certainly
better than the inactive ones, but they are not magic, you
shouldn’t rely on them to do the cleaning for you.

So, now you have a nice clean joint and a flux, so it’s plain
sailing, yes? Well almost. Most problems are caused by heating the
solder rather than the joint. All that happens is that the solder
melts, goes into a ball, and refuses to flow into the joint because
it freezes before it can wet it. The secret is to heat the joint, not
the solder. When the joint gets hot enough it will melt the solder
which will then flow nicely into the clean, fluxed joint. The final
thing that can go wrong is to burn the flux. If you heat the flux for
too long, longer than a minute or so, it will lose its properties and
allow the oxygen to pass. This is normally the result of insufficient
heat, so if it happens, remove the heat, clean the joint, and start
over, perhaps with a better source of heat, or better insulation to
prevent the heat from leaking away.

So, the four main points for a good soldered joint aRe:

  1. Make sure the joint and solder are both clean.
  2. Use a good appropriate flux.
  3. Heat the joint not the solder.
  4. Complete the joint quickly.

I hope this helps.
Regards, Gary Wooding

4

Since none of us are looking over your shoulder you’ll have to
figure this out yourself.

If you’ve had success before and then suddenly one day…zilch,
obviously something changed. I suggest you not take for granted
things like, ‘its the same solder.’ Double check, could you have
accidentally picked up something that merely looked like the solder?
Heat…same flame? or is it more oxidizing now? Flux…you didn’t
mention flux, double check that you indeed are using flux and not
something you might have mistaken for flux. Are you cleaning the
metal after a failed solder in prep for another try? You would need
to pickle in this case, but on fresh metal its not needed.

Relax though, its something simple that has been overlooked. You did
it before, you’ll do it again.

5

Linda,

Are we talking about silver, white gold or gold?

You are correct in trying to eliminate gaps. solder does not like to
jump them.

The piece must be clean before you begin. No need to pickle in
advance, that’s why you use boric acid and denatured alcohol. When
you dip it and light it, it creates a glass barrier that helps to
prevent firescale. Firescale is the reason solder will only stretch
so far. Firescale is essentially ‘dirt’ on the metal. I heat the
piece just a bit and the sizzle a bit of flux where I’m going to put
the solder. As soon as I see any movement at all, I flux the other
side of the joint and more along the line where I want the solder to
go.

When soldering gold, solder will stretch most anywhere you want.
It’s different with white gold and silver. With silver the answer is
flux, flux, flux. Flux removes the oxygen from the joint making room
for the solder to flow. Silver and white gold tend to ‘dirty’ faster
than gold and must be pickled, steamed and wire brushed often when
trying to stretch solder.

I do not attempt to heat the entire piece before solder, just the
area, keeping the heat on the heavier piece close to the joint and
moving back and forth. If you see the metal glow red-stop, the
solder should have flown. If you proceed at that temp, you overheat
the solder and begin having problems. Clean and begin again.

Another tip is ‘heat-sinking’. This is to equalize the weight of the
pieces to be soldered. Using a bezel as an example, you know to
always put the solder on the heavier piece. Then you touch the
lighter piece to it. Lay the butt end of your tweezers parallel on
top of the bezel above the joint where you are soldering. This will
make the heat go sideways rather than attempting to melt the top edge
of the bezel. Hold this pair of tweezers in your hand. If you see the
solder going to the heavier piece, momentarily lift the tweezers and
it will flow to the lighter piece as long as the so lder is touching
both pieces and there is flux in the joint.

Happy jewelering,
J. Rose

6

Linda,

Sometimes it really isn’t you, but the solder. I have had bad lots
of solder over the years to the point where my silver cracked from
heat and the solder didn’t flow. Have you used this batch of solder
previously? If not then I would send it back to your supplier and
tell them to please exchange it.

Jennifer Friedman

7

Linda,

Where did you purchase your solder? Do you know what the flow
temperature is? Look at the difference between the hard solder of
Hoover and Strong and DH Fell. Often Rio’s hard solder will just sit
there, glow and not flow. You really have to put heat on it, same
with Hoover and Strong.

Students and instructors have thought, maybe I have wire instead. If
you are heating your solder and it is sitting there, the surrounding
metal is not hot enough, and you are burning off the alloy which
allows your solder to flow. You could sit there all day and nothing
would happen.

Have you changed your solder from two days ago? Is your solder
clean?

It won’t matter if you have pickled your metal, but it will matter
if you have burned off the alloy.

The important part here is that when something used to happen fine
and now it doesn’t, you have to take a step back and say, what did I
change?

Get some fresh solder, snip a tiny chip with the solder you are
using now. Heat them on a piece of test metal that hasn’t been
pickled and one that has. You are doing the technical portion of your
process and you must at some point step back and become the
scientist.

I’m reposting an older post on silver solder flow temperatures.

This is an excerpt of the longer post which has the quick and low
down on silver solder temperatures.

Silver Solder Wire Flow Points

Hoover and Strong Best color match to sterling silver

Easy 1250 F
Medium 1295 F
Hard 1490 F

Rio Grande Good color match in Easy and Medium

Easy 1325 F
Medium 1360 F
Hard 1450 F

Hauser and Miller Slight yellowing in their solder, but good for
beginners

Easy 1325 F
Medium 1360 F
Hard 1450 F

DH Fell Good color match and good flow for all solders. Just be
mindful of their temperatures if you are mixing one vendors with
another.

Easy 1240F
Medium 1275 F
Hard 1365 F

8

Has anyone noticed that solder does not flow well when there is a
full moon. When I was teaching a large beginning class in Jewelry,
we would notice that everyone had trouble about one or two days a
month. After looking at the calendar we would see it was a full moon.
No scientific fact here but it sure happened more often than not. So
now if I am having trouble I just call it a holiday and it is a great
excuse to go fishing.

Coit

9

I have not noticed this as a fact. But I will definitely observe the
tradition you have started of going fishing. You are a person after
my own heart.

Keep shinning your metal and a tight line,

Ken Moore
www.kenworx.com

10 
Has anyone noticed that solder does not flow well when there is a
full moon.

Yes indeed, at least for some people. After they finish turning into
werewolves, they not only have trouble handling the torch skillfully
in their paws, but they tend to become distracted easily, sometimes
even setting their fur on fire, and generally forgetting the basic
rules of proper soldering technique.

High tide also makes it difficult to solder for those who insist on
doing so at the same water’s edge workstation they can use at low
tide. (the waves tend to rinse off the flux, so the solder won’t
flow.)

cheers
Peter

11 
Has anyone noticed that solder does not flow well when there is a
full moon.

My opinion is that those of us who do this for a living are ignorant
of this phenomenon…therefore not affected by

Today I showed an opal pendant to a customer and she said “I can’t
wear them because they are not my birthstone”, and I replied “Oh you
fell for that old wife’s tale?” And she replied that she had
experience that it was true. I told her that I thought diamonds were
unlucky as 50% of marriages fail, and it must be the diamonds that
were the problem. Her friend was laughing while she was trying to
screw her brain around that.

Richard Hart

12

Many thanks for all your advice but I’ve just tried to solder again
and once again the solder doesn’t take. I have cleaned the silver by
sandpapering it down and have done the same with the bezel wire and
solder.

It is a bigger setting but have done this type of setting before and
it worked. The strange thing is when I solder the bezel with hard
solder it works but when I try and solder it to the back plate it
doesn;t!! I was using hard solder for the bezel so tried hard solder
for the backplate but no success. It still just doesn’t take. It is
really puzzling as it was working a week ago and now it isn’t. I
really don’t want to give up on this but I am becoming extremely
frustrated and have hardly any bezel wire left as I keep burning
through it. I may need to take another class to find out what is
wrong. Is this something that other people have gone through? Am I
totally off track? Yours frustratingly, Linda

13 
I've just tried to solder again and once again the solder doesn't
take. I have cleaned the silver by sandpapering it down and have
done the same with the bezel wire and solder.

We had this problem once for a few weeks in a college I taught at.
the flux we used was borax cone and water, changing to distilled
water ‘seemed’ to solve the problem. Thats is if you use water in
your flux.

mary

14

Linda,

It sure sounds like not enough heat… too small a flame and/or
torch.

All of the other variables are pretty easy to see and check, other
than mixing up your solder with a piece of silver or the cat peeing
in your flux (personal experience with only the first, but they are
nasty little monsters:-).

Keep at it, you will succeed and have learned a lot. Silly dumb
things do really bite, but you’ll never do that one again.

Classes help but there is a world of difference between what you are
taught and what you learn.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand

15

Hello Linda ; silver is more difficult to solder than gold, and the
most importat things about soldering silver is that you have to heat
the whole piece generaly, but if you have cleaned the metal in
pickle and are not burning away your flux by heating for along time
and you are heating the entire piece it should work.

One other little point…one time a friend of mine had a similar
problem and when I investigated I found that what he thought he was
solder was actually silver wire. That’s why labeling your wire right
away when you bring it in the shop is important, if you are confused
put it into the flame if it doesn’t ball up in a fairly quick time
it may be silver.

However most of the time either the flux is cooked off, the metal is
dirty, or you don’t have enough heat or heat in the right area, if
you are burning up your bezel it is obviously getting too much heat,
try heating the sheet base that the bezel is sitting on from
underneath and then bring the flame around to the top side to heat
it up evenly that way the bezel won’t get over exposed and burn up,
and remember solder will go where the heat is, if you want to solder
a bezel to sheet you better heat up the sheet more than the bezel.

I probably confused you, and Iwish I were there because I know you
can “get it”

Frankenstein

16

Linda, don’t know but maybe this will help: solder flows from cold
to hot, remember to heat the joint from the opposite side that you
are applying the solder. this way when the metal on the “cold” side
gets hot enough to melt the solder it will flow to the “hot” side
where the torch/iron is.

John
John Atwell Rasmussen
Rasmussen Gems and Jewelry
www.rasmussengems.com

17

Hey Linda,

It is a bigger setting but have done this type of setting before
and it worked. The strange thing is when I solder the bezel with
hard solder it works but when I try and solder it to the back plate
it doesn;t!! I was using hard solder for the bezel so tried hard
solder for the backplate but no success. It still just doesn't take

I think the key to your difficulty may be in the size of the new
larger setting. Silver will diffuse heat more quickly than other
metals, and while a smaller piece will get hot enough fairly
quickly, a larger piece will require more time/heat to come up to the
same soldering temperature. You can get around this problem by using
a larger flame and bringing the entire piece up to temperature before
concentrating on the bezel. Keeping the heat on the back piece will
help to prevent bezel meltdown. My experience is paste solder is the
best for silver. It stays active for a longer period of time and
doesn’t burn off before your solder flows. Another thing to try is
to use a lower temperature solder to attach the bezel to the back
plate. I usually use hard solder to solder the bezel together, but
then use medium or easy to attach the bezel to its backing. This
technique will also help to prevent the solder line in the bezel from
showing up after the soldering is complete.

This is all a normal part of the learning curve, just keep adjusting
your technique one thing at a time until you achieve the results you
are after! That way you will understand what works, and why.

Melissa Veres, engraver

18 
It is a bigger setting but have done this type of setting before
and it worked. The strange thing is when I solder the bezel with
hard solder it works but when I try and solder it to the back plate
it doesn;t!! I was using hard solder for the bezel so tried hard
solder for the backplate but no success. It still just doesn't take

Silly question from a beginner: Are you using the same torch? I’m
sure you are but this sounds like the problems I was having with
simply not getting the metal hot enough with my creme brulee torch
(BLT - Before Little Torch). I could solder bezel and wire rings with
no problem but the butane torch was just not up to 14ga sterling.

19 
It is a bigger setting

Well there’s the something that changed. The mass. Try going to a
larger torch tip.

hardly any bezel wire left as I keep burning through it

Ok, once you have corrected the torch problem…heat the backing, not
the bezel. Let the heat seep to the bezel. You can lightly lick the
flame over the bezel but don’t hold it there. While soldering inside
the bezel gives you the neatest finish its also harder to do, you’re
first job is to get it soldered at all. Make the sheet significantly
larger than the bezel, solder on the outside playing the heat on that
sheet ‘extension’. Use a heat sink on top of the bezel if you need
to. Trim off excess sheet after soldering.

20

Can I just say thank you all so much for showing such generosity in
sharing your expertise with me. I have only been on the forum for a
short time but it has made such a difference! I think I am narrowing
it down. When I solder the bezel it works! so this means I am using
solder. It is when I am attaching it to the fine silver backplate.
Because it is not working the first time I am pickling the backplate
then sanding it down (but not with harsh sandpaper). You have made
suggestion on how to clean the silver.

I will definitely look into this as I am not confident that I am
properly cleaning it. The other thing that I am not confident about
is the torch and whether I have the right one and is the flame set at
the right strength. I will also check this out as well. Thank you all
for keeping my hopes going. I’m certainly not going to give up that
easily!!

Once again many thanks for all your help.
Linda, Leicester, UK