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Soldering simple sterling silver tree


#1

I’m taking a class in soldering. By next week I need to solder a
simple sterling silver tree (all branches, no leaves, made 15 gauge
wire, total length of wire is 3 inches-see photo below) to a piece of
flat sterling, 20 gauge, about 1.5 by 2.5 inches. I also attempted to
do this out of brass first.

After about 8 attempts with brass, and 4 with silver I still cannot
get the wire to adhere to the sheet. I’ve tried thicker flux, a
larger flame, and heating the sheet until practically burnt. I
pickle between attempts. The wire has been flattened on the back by
hammer and further flattened by sanding. The medium solder flows fine
on the wire, but just won’t adhere when I lay it on the sheet. The
torch is supplied by the classroom and I think I’m adjusting the
flame correctly and using the hot spot. The sheet is slightly raised
off the firebrick by 2 binding wires so I can direct the flame
beneath the sheet.

I need this completed for class by next week and don’t have access to
any other help between now and then - what else can I try? I’ve
already melted one silver tree and will need to make a trip to buy
more brass and silver wire if told to start again from scratch.

Mary Partlan
White Branch Designs
www.whitebranchdesigns.com


#2

Have you tried cleaning the sheet? It could just be dirty or have a
coating of some kind on it.

Lindsay


#3

Hi Mary,

It sounds to me that, although you’ve been shown how to solder, you
haven’t been told how it actually works. Understanding the mechanics
makes it easier to figure out why it sometimes doesn’t work. At the
risk of boring those who have read this before, here is a repeat of a
posting I made back in August…

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.

JOLT (Just One Little Thing), solder flows into a joint by capillary
attraction - its not good at filling gaps, but some solders are
better than others. The items to be joined must fit reasonably well;
if the gap is too big or too small the solder won’t flow properly.
Around 2-5 thou (.002"-.005", or.05-.1mm) is about right, but its not
overly critical.

I hope this helps.
Regards, Gary Wooding


#4
The medium solder flows fine on the wire, but just won't adhere
when I lay it on the sheet. The torch is supplied by the classroom
and I think I'm adjusting the flame correctly and using the hot
spot. 

Chances are that you have a gap between the plate and the wire. Make
sure that wire lies on the plate absolutely flat.

Try this:

Anneal and pickle both parts. Scrape the plate bright. File the wire
so it would lie flat, without any spaces. When done, degrease both
parts. Washing with hot water and soap will do. Run solder on the
wire and file flat again but leave some solder on it. Flux both
parts. Flux should be evenly applied. If it beads up, the metal is
not clean. Dry pieces with very soft flame. When soldering do not
use hot spot. Flame should be soft and bushy with some yellow in it.
Heat from under until solder flows and not a moment more. It helps to
turn of the light, so you can see the color of the pieces. If color
is not even, you are not using flame correctly. Manipulate torch so
all pieces to be soldered are at the same temperature.

Leonid Surpin
www.studioarete.com


#5

Did you sand the surface of sheet where the wire is to be soldered?
This may help. As well, try floating your solder on the sheet and
laying the wires on top. Solder goes towards the flame, so your
problem may be just that (if you are firing from above). A trick
that works for me really well is to actually build a little 'table’
with dress makers pins in a perforated fire brick or stick them in a
soft charcoal block, and lay your sheet on the tops of the pins. Flux
really well. The pins shouldn’t solder to the silver- I have never
had it happen, but it is possible, so be careful. If they do solder
on, just cut them off and file away any leftover bits. Your torch
flame will have much better access to the underside of your piece,
and the solder will flow with more ease. If you have fired the same
piece numerous times you may have some firescale to deal with.

Hope this helps! Good luck :slight_smile:


#6

Hi Mary,

You will probably get lots of replies - here is how I do it - prop
the background silver sheet on top of two soldering blocks that have
a space between them, then after brushing the top with your torch so
that the solder snippets are held in place, apply the torch directly
under the background sheet with a fairly high heat - brush the flame
back and forth and heat until the solder flows. That way the
background sheet will reach soldering flow temp. at the same time as
your wires. You can hold the edge of the background sheet up with
tweezers too (non dominant hand - torch in dominant hand) if that
works better for you.

Good luck - its really fun once you have mastered it.

Jan
www.designjewel.com


#7

Mary,

Remember, you don’t have to solder everything in place all at once.
Tack it in several places with hard solder to get your "tree"
stabilized. If you are using wire, make sure it is flat on the back
for maximum solder contact. The more surface area you create for
your solder, the more solid the connection.

Solder goes towards heat, so heating from underneath is good. Just
watch how close your flame is to the metal.

If you don’t want to risk the solder moving while drying out the
flux, set up your piece and just walk away until the water has dried
out of the flux. The bubbling action is just the water evaporating.

Most important, do a dry run with your work set up and torch off.
This simple step will take away the stress of soldering and allow
you to shift your position if needed before you actually solder.

Good luck!
karen christians
cleverwerx


#8

I think your problem is the heat is not getting to where its needed
in enough quantity.

If you prop up the sheet and heat from the back, with a piece this
size you run the risk of heat/pressure distortion…sagging. The heat
won’t transfer from sheet to wire so easily because the wire is
hanging out there in open air, cooling off…heatsinking. You need
the heat ON the join after a thorough preheat.

Use a soft flame and play the heat from sheet to wire repeatedly,
until you see the flux getting shiny, then start to concentrate the
heat to the join. Assuming the torch is large enough I think you just
need to be braver.


#9

Soldering accomplishments since my original post:

two 4 hour sessions in the lab, a 3 hour class, a large painful
bruise where I walked into the end of a ring mandrel protruding into
the aisle, bent points on my 6 week old soldering tweezers purchases
of new wire, solder and sheet

… and my piece still hasn’t soldered properly.

Thanks for all the responses I received. I’ve consolidated all your
suggestions (even when contradictory) to carry with me to class.
Special thanks to those who also offered encouragement and sympathy.
I haven’t given up yet, but must admit there have been quite a few
moments of despair. As soon as I have time for my blog I’ll post
photos of the work and my experience, and hopefully, the finished
piece. It was a big consolation to learn last night that most of the
other students had similar difficulties and were not ready to proceed
to the next step, adding a bezel. I can’t wait to see how many of
those I melt.

Mary Partlan
White Branch Designs
www.whitebranchdesigns.com


#10
... and my piece still hasn't soldered properly. 

I’ve taught metalsmithing since 1992. The whole thing about soldering
is even heating.

The majority of the time, if a student says, "this won’t solder,"
and I sit with them and watch them solder, the problem is uneven
heating. Once they fully realize, “Oh, she really means it, if even
one section of the piece of metal gets cold, it won’t solder,” then
they are successful.

The other thing is good hand control – sometimes people are waving
the torch around somewhat wildly. Move the torch in good, even,
consistent movements around the piece, never letting any part of the
metal get cold.

Ask your teacher to sit and watch you solder, then he/she will be
able to diagnose your particular error.

Keys to soldering:

Clean, fluxed and touching plus even heating.

That’s all!

Elaine
http://www.CreativeTextureTools.com