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Problem soldering silver: Pits


#1

Hello,

This is my first post, so I apologize if this is in the wrong place,
wrong format, etc. That aside, let’s start with a simple problem:

When silver soldering, sometimes I get a pit right where the solder
chip was sitting. Many times I do not… sometimes I do. It never
happens when applying solder with a pick, so I suspect it has
something to do with the solder sitting there on the hot silver for
too long. I always prepare a clean surface, use flux, heat the piece
not the solder, etc. Just wondering:

  1. Scientifically, what causes this? It’s curious to me that the
    silver sheet below the solder actually LOSES quite a bit of material
    in the transaction… and forms a big ugly pit - where does it go?

  2. How to ensure it doesn’t happen? Just use the pick? Heat the
    silver more quickly? Different kind of flux?

One observation: This has happened more, recently since I got a
Smith Little Torch (oxy/pro). I have not had this problem for years
previous when chip soldering with a $12, hardware store propane/air
torch.

Thanks for any help!


#2

David- I always add my solder just as the metal reaches soldering
temp. If you add a chip and then heat the metal up you will end up
burning away some of the alloy that makes it melt at a lower temp.
Thus the pits. Another tip is that if you don’t get the soldering
right the first time and try to re heat the solder it will be a
slightly higher melt temperature and get higher each time you reheat.
If I don’t get it right the first two times, I remove the solder and
start over with fresh. I’ve seen so many folks just reheat and reheat
until they melt the whole thing.

Have fun and make lots of jewelry.

Jo Haemer
www.timothywgreen.com


#3

I prefer a pick for control. When using the pick one must know when
the exact, correct time is to place the little solder ball on the
joint. The answer is: When it gets salty.


#4

As with all soldering if you just reheat and don’t pickle and clean
the area before reheating your chances of getting the solder to
re-flow correctly and not pit are less. Pickle, rinse, re-firecoat,
flux, re-heat and if needed add new. You might also drag the
soldering pic through the soldering joint to smooth it out.


#5
I prefer a pick for control. When using the pick one must know
where the exact, correct time is to place the little solder ball
on the joint. The answer is: When it gets salty." 

Salty? What do you mean by that?

Jerry in Kodiak


#6
If you add a chip and then heat the metal up you will end up
burning away some of the alloy that makes it melt at a lower temp. 

Let’s clarify what Jo means. Placing the clipping of solder on the
work below solder flow temperature and then raising the temperature
of the work and solder at the same time to obtain solder flow, is not
optimal. Furthermore, I am certain she is adding a clipping, not a
ball of solder, from a pick to the work. Preheating the flux on your
pick will stick and transport the unmelted clipping of solder. The
point is not to melt the solder prior to placing it on the work. The
art here is knowing when the work temperature is correct. Often flux
and work will give you an indication of work temperature. The flame
is moved rhythmically away from the solder placement point as the
clipping is placed, which instantly begins to melt and then the flame
returns momentarily to the point the solder is placed to ensure deep
capillary action of the solder into the joint. For those of you who
are masters of your craft please humor me and disregard this post. Jo
please don’t be offended by my lengthy clarification. For those of
you who are learning to solder please take this gem of wisdom from Jo
as a gift. I also believe this to be the best technique. Please note
that this technique is for solder clippings and manual oxy/gas torch
soldering. Pre-placement of paste solder on the joint results in
optimal solder joints in furnace soldering technique.


#7
Salty? What do you mean by that? 

It’s a joke. One must place ones tongue on something to determine if
it’s salty or not (although Peter Rowe probably knows a more
scientific/geeky way.)

After working with metals awhile, one just develops a sense as to
when the metal is hot enough for whatever one is doing, i.e.,
soldering, annealing, etc.


#8
Let's clarify what Jo means. Placing the clipping of solder on the
work below solder flow temperature and then raising the
temperature of the work and solder at the same time to obtain
solder flow, is not optimal. 

I have never used any other technique, but the one which is
described as not optimal. I cut my solder into paillon; place paillon
on joints; and heat until solder flows. It does require higher degree
of heat control than other techniques, but results are far superior.

Leonid Surpin
www.studioarete.com


#9
It's a joke. One must place ones tongue on something to determine
if it's salty or not (although Peter Rowe probably knows a more
scientific/geeky way.) 

Yup. Use someone elses tongue. That’s called an impartial observer,
or test subject if you like. Has the major advantage that if it’s NOT
salt, is highly toxic, or is way too much, or otherwise nasty, then
you didn’t go foolishly sticking it in your mouth…

So off the top of my bald head, no I’m not sure how to quickly tell
if it’s table salt beyond tasting or having someone else taste it,
without some fuss and bother. But one test you CAN do, is place a bit
of your unknown in a nice hot neutral flame. You’re a jeweler, so you
should be able to arrange that, right? The color of the flame after
it brushes over the sample can tell you things about what it
contains. Salt contains sodium. The sodium flare is bright yellow…
Of course, there’s sodium in lots of things, so this only checks for
sodium, not whether it’s salt, and perhaps not even if it was your
sample, rather than some risidual flux residue on your test surface
that caused the flare. But doesn’t matter. Pretty pretty flames are
just fine, no matter where their mesmerizing colors come from as you
stare deeply into the blinding bright yellow color…

Opps. sorry. (returns from trance…)

Or if you wanted to get really geeky, view the flare with a
spectroscope. Make a major fuss over setting this whole thing up for
maximum effect. You most likely won’t be able to get useful
from this observation, both because your gem spectroscope
might not have callibration markings to make lines specifically
identifiable, but mostly, because you probably only have the
spectrocope, and not the knowledge of how to use it this way. But
that doesn’t matter at all. A bit of confident sounding BS will do
just fine in place of actual results. It will look really cool,
impress your friends, Could possibly be recorded for YouTube, and
might even help you get the girl.

(or not. She might not actually be into lying fake geeks with salt
on the brain…)

Cheers
Peter Rowe


#10

Thank you. There are so many “instructions” that show placing the
chip on the joint and heating everything at the same time. The
previous post also explains why I melted a piece trying to
reposition a soldered piece that I miss positioned several times
during soldering.


#11
Placing the clipping of solder on the work below solder flow
temperature and then raising the temperature of the work and solder
at the same time to obtain solder flow, is not optimal. [snip] The
flame is moved rhythmically away from the solder placement point as
the clipping is placed, which instantly begins to melt 

This (truncated) quote describes what I learned as “pick soldering”,
though I learned to to it by melting the chip of solder into a ball,
touching the pick to it (it sticks, usually) then placing it at the
correct moment and spot. It is a wonderful technique, but I have only
made a habit of using it when gravity would not hold the solder where
I want it, such as to close a jump ring.

The post I am quoting from seems to imply that pick soldering is
best as the default method, and that it should be done without
pre-melting the solder.

As a largely self-taught metalsmith, I wonder whether this is a
widespread notion. I have often had the experience of having pits,
sometimes large ones, left in the surface of silver where the solder
sat before it flowed into the seam. It seems to happen most often
with easy solder, so, naturally, close to the end of the fabrication
when it is the biggest PITA to correct or disguise.

It never occurred to me to avoid this possibility by pick soldering
where I would not have considered it necessary-- that is, where the
chip of solder will stay put adjacent to the joint. Do you old hands
at silver work actually pick solder in this situation, or is the
above just one person’s POV?

Noel


#12

I guess it is time for another soldering argument.

Problem - solder pits. Cause - solder over-heating. Does not matter
which method you use, if solder gets over-heated, it is going to be
a problem.

Pre melting solder is done to raise flowing temperature. If you run
out of hard solder, pre melting medium solder, may do the trick.
Also, pre melted solder, does not reflow easily. However, there are
better ways to control reflow.

Pick versus placement - I do not use solder picks, because I
consider technique too risky. With placement, I have all the time in
the world to place solder, exactly how I want it. With pick, chances
of misplacement are too high for my taste.

Placement and heating allows for the greatest degree of control over
soldering process. One caveat is that flame must be adjusted
intelligently. The problem people having with placement is that
torches are too hot. Soft, bushy flame does the trick.

Leonid Surpin
www.studioarete.com


#13

The biggest problem I have with placing a chip is that that its
irregular cut shape can wobble back and forth in the hot flux before
settling.

Some tips are below if you are interested, but one thing to note for
sure. Less is more. People tend to use large logs to solder instead
of something tiny. You can always add a little more, it’s hard to
take away. Tacking a piece in solder will help greatly, but not for
the final solder.

Solder flow temperatures are not linear. Despite the name of Easy,
Medium and Hard, Easy to Medium is about 2/3 in a straight line,
meaning, Medium is not half way, its nearly 2/3 the way to Hard in
temperature.

  1. Flowing solder with Easy solder depends a lot on the manufacturer
    of your solder. Hoover and Strong’s easy solder has a fairly high
    melting point and in my humble opinion one of the best for both color
    match and flow.

  2. Quenching in pickle can create pits, so I would avoid this if is
    a common practice.

  3. DON’T RUSH. Rushing or trying to work too quickly can create
    problems. Soldering is a cinch if everything is clean, prepared for a
    good fit and everything is in place.

  4. Pick soldering - preflowing solder. Be very, very careful. If you
    do this kind of soldering, which I like, you must be very mindful not
    to overheat your solder sphere.

  5. If your solder glows, you are burning off the alloy making it
    flow. It can eventually break down if you do it over and over.

  6. Heat your solder to a just balled state on charcoal, heat your
    pick with flux and walk your solder pick over to your ball. The ball
    should jump onto the pick without getting to hot. Then move your pick
    to a fluxed area which is heated and sticky. Drop it onto the hotter
    sticky flux. Wait a bit and begin heating slowly.

  7. give your piece 5 seconds after soldering and before quenching,
    especially when you are at the end and using Easy. If you have a
    heavy piece and are soldering a bale or some small piece at the end,
    the mass of the heavier metal is maintaining heat. Giving the solder
    a few seconds to bond tightly before a thermal shock will prevent
    pitting.

Happy soldering!

Karen Christians
Cleverwerx


#14
Do you old hands at silver work actually pick solder in this
situation, or is the above just one person's POV? 

I always pick solder regardless. And I use the dreaded borax/alcohol
mess and never have pits. FWIW I think too much heat causes pits in
silver regardless how you get the solder to the piece.


#15

Noel,

There are a whole series of issues in soldering that can be avoided
if you use a pick to place the solder on a joint heated to the flow
temperature of the solder. It is not the only way to achieve a good
solder joint but it is a reliable one if you don’t overheat the
solder while it is on the end of the pick.

The main reason for pits directly under the solder pallion when you
use the place the pallion then heat the work method is that the heat
is brought up too slowly and you have liquation problem where the
low melting alloy flows out of the solder and takes some of the base
metal with it If you examine these areas closely you will also often
see a remainder or skull of the solder pallion on the surface of the
work… If the work is heated rapidly enough this is not so much of an
issue. It happens more often with easy solders also.

James Binnion
James Binnion Metal Arts


#16
The biggest problem I have with placing a chip is that that its
irregular cut shape can wobble back and forth in the hot flux
before settling. 

Melt your snippet to a sphere on the charcoal block. Heat your piece
and lightly firecoat. Dip the ball into a small puddle of flux.
Place the ball where needed on the still hot piece with sharp
tweezers only long enough for the flux to quickly dry on the ball but
not on the tweezers(if the tweezers get white the ball will come off
with the tweezer)… The flux becomes hot glue. Takes practice but is
not hard. If the situation is such that the ball still wobbles and
weebles try this…after balling the solder, place it on a bench
block and whack it with a flat faced hammer before placing it on the
piece. Why a flat faced hammer and not say a ball peen? Its not so
the solder has a perfect flat, at that size it doesn’t matter. Its
simply so the solder ball doesn’t go shooosting across the bench and
into no man’s land. I use this a lot for retipping where placement is
critical and heat sink from a pick is a drag. This also works with
platinum except you have to be quick with melting the ball(on an
appropriate platinum soldering block ofcourse) or you may find the
ball is stuck fast to the block. No,you wouldn’t retip with platinum
solder,in case that clarification is needed!

You’ll find that the round ball method allows you to fit it into
really tight places. It generally doesn’t burn into the surface the
way snippets sometimes do, if your touch is good.


#17

Hi Neil,

This is one of those instances that there is no right or wrong way to
do a process; just the one that works best for you. I like pick
soldering and it works for me. I use my flame in my dominant hand
and trained my other hand for the placement operations. There is no
right or wrong, or best or worst. The goal is to have a perfectly
soldered piece that is strong, durable and looks clean. How one
achieves the path to a goal is up to the individual doing the
traveling.

Karen Christians
Cleverwerx


#18

Hi All,

Pits in your solder joins are from the solder not melting completely
OR… you have not used enough solder at that particular place. Pits
can also come from the areas not being clean at the spot where the
pits happen. Not being clean enough is not usually a problem with
paste solder, by the way, as it is has much more "self cleaning"
ability than many other fluxes by the nature of the flux contained in
the paste.

The trick to avoid pitting is to heat the metal around the area and
not directly on the solder and thus dissipating the flux. You need to
bring the metal to the melting temperature required by the grade of
solder you are using. You then have to continue heating past the melt
temperature until your reach the flow temperature of the solder. At
the point where it is just about to flow, you can direct your flame
to the area you are concentrating on joining and remember that solder
flows toward the heat. You can draw the solder through the join and
make it a very smooth seam. If you are getting some pitted appearance
when the solder is shiny (liquid flow stage) and the solder is not
filing in the gaps and you are seeing (pits), then simply use a
soldering pick to go over the seam at that point and smooth out the
solder so it will fill in those gaps while the solder is still hot
and flowing. Note that if the seam (join) is not tight, no matter
what, the solder will not entirely fill the gap and you will have a
space. Happy soldering.

Beth Katz
http://www.myuniquesolutions.com


#19

Norman,

Did you know that you can pick solder with paste solder? Simply
extrude (from a syringe) and place a small amount on the tip of a
soldering pick. After the solder is on the pick, just apply a small
amount of heat to the pick up from the tip so the solder does not
roll off, but forms a small ball at the tip of the pick. Works every
time once you get the hang of it. If you are using some paste solder
from a jar, you can heat the pick in advance, dip into the paste
solder in the jar and pick up a very small amount of the tip. You may
have to heat a little more to get the solder to ball. If the solder
ball is not exactly at the end, you can use the side of the torch tip
to move the solder to the end of the pick. Tricky but once you master
it, you will like the new technique.

Beth Katz
http://www.myuniquesolutions.com


#20

I’m not as old as I hope to get. But my preference is pick soldering
with melted balls, maybe pallions or stick 5% of the time. O/A torch
in dominant hand, I am not too subtle about soldering.

For me there are only 2 places for easy solder… the drawer or the
refiner. I start with hard (or better) and finish with hard. Nothing
falls apart and the colour is almost nice, no pits. OK I will confess
to using easy on mystery metal findings :slight_smile:

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