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Sudden failure when soldering silver rings


#1

I need help. After making hundreds of rings without a problem I can
no longer get a good solder seam.

I started to make rings in 2009, made approx 400 rings since then,
mostly wide pipe bands, spinner rings, plain bands out of sterling
silver.

Last December I started to experience cracking solder seams. The
solder seems to flow, but when I round the ring on the mandrel the
seam cracks open. I cleaned out everthing and the problem went away.
Since then I made about 50 more rings, no problems. Now it is
happening again. Again, I cleaned out everything, this time the
problem persists.

What I tried:

  • Cleaned all solder, plus tried different batches/types of solder
  • Used fresh flux and new batch of fire coat.
  • Cleaned brushes
  • Cleaned torch tip with copper wire, then ultrasonic.
  • Sanded titanium solder pick
  • Dusted and cleaned everything off.
  • sanded my titanium solder pick clean

Materials I am using (nothing new):

  • Meco Midget torch with Propane and Oxygene
  • Sterling silver from Hauser and Miller, Rio and Hoover and Strong
  • Usually I use hard silver solder from Hoover&S and H&Mi Also tried
    some medium silver solder I had left from Otto Frei. Experienced
    failure with all.
  • Usually use Yellow self-pickling flouride free flux from Alpha
    Supply, also tried brandnew bottle of yellow Aquaflux. Tried white
    paste flux, same issues.
  • Firecoat made by mixing boric acid (from jewelry supply store) and
    Isopropyl alcohol.

My process:

  1. Cut ring blanks, file ends, form to roughly round (somewhat "D"
    shaped) so ends meet flush. Make sure there is no daylight visible
    thru the seam.
  2. Dip ring in boric/alcohol mixture.
  3. Put ring in third hand, seam at the bottom.
  4. Burn off alcohol.
  5. Add flux to seam.
  6. Cut solder with solder nipper.
  7. Place hard silver solder pieces over seam with flux brush.
  8. Flame is bit less then an inch long, with bit of orange on the
    tip, soft, no hiss. I heat up the top of the ring away from the
    seam. As the metal gets close to hot enough I move the flame
    underneath the ring, where the seam is to pull the solder thru.

I usually get clean, solder-pit-free, invisible seams that only
require a few swipes with sand paper to clean up. I have not changed
this process at all as far as I can tell and am at a total loss why I
am suddenly having problems. I have photos with closeups of a
cracked ring on

I have orders to fill and I am desperate to get his figured out, so
I can continue to work. Please let me know if you know what is
causing the problem.

Thanks, Birgit
(I am in Snohomish, WA, just north of Seattle in case anybody local
would be willing to help me figure this out).


#2

It looks as though the solder is not travelling along the whole
length of the seam. This could be because the metal is not heated
enough over the seam area to make the solder “wick” bycapilliary
action thoroughly or there isnt enough solder. I note there is a
little bit of pooling on the inside of the ring where the solder
presumably has been applied. That is quite common when the area
around it isnt quite hot enough for it to flow to. A bigger flame
will help with this, not necessarily hotter but giving better heat
conduction to all of the seam. Are you keeping the fire coat away
from the flux? They are both borax based but Argotect and the like
play up with other flux compounds. THis could mean your joint is
filled with flux and not solder. A bigger flame will have a bigger
reducing area which is hot enough to work with and so reduce the
need for an anti-firestain coating.

Best regards,
Nick Royall


#3

Hello Birgit,

Judging from your photos it appears that the solder hasn’t
completely filled the joint. Possible causes aRe: not enough solder,
seam not completely closed, or incorrect heating. Possibly all three.

Regards, Gary Wooding


#4

Hi,

It sounds like the solder is not penetrating past the surface of the
silver, into the metal, so I’m making this suggestion to adjust the
heating method:

start off by heating the whole ring, rather than the top. Then, heat
the entire lower half of the ring, rather than just the joint. I wish
you a speedy resolution to the problem!

Cindy
http://www.cynthiaeid.com


#5

Birgit,

you have not mentioned the thickness of the bands material.
Specially for thicker material bending the shank to a D-shape before
soldering is not a good choice (I think), too much stress on the
outside that has to stretch a lot when you hammer the ring on the
mandrel.

I always bend the ring round before soldering, and then saw
(straight) thru the V-shaped gap, close the ring further, saw again,.
until I have an accurate match of the ends inside and out, no light
shining thru. When calculating the length required for the shank I
always round up a bit to cover the loss using this method.

But maybe someone else will answer that you just stopped the
soldering process before the solder had a chance to really integrate
with the silver.

Good luck
Sylvia


#6

Birgit - I’d guess that one of three things is happening -

You could be boiling the solder by applying snippets. Try instead
melting the solder gently, picking it up with your clean solder pic,
heating the joint to where your flux indicates correct heating and
then touching the solder ball to the joint on the opposite side from
the torch flame. Use it edge to edge first, then go inside and gently
pull it thru. If your joint is hot enough, it should go all the way
thru first time.

Second, I don’t know what tip you are using on your rings, but with
my Meco Midget, I’d use a #3 ventilated tip to get enough heat on the
piece.

Third - you might not be getting flux inside the joint - have you
tried using a tweezers to pick up the flux and capillary action to
pull it inside the joint.

Your flux from Alpha Supply may have simply aged and lost one or
more of its chemical elements. Alpha has been out of business for
several years - at least their website is gone and they haven’t paid
my bill for product that they ordered… I have some old flux that
lost its yellow color and quit working - don’t know why except it is
old.

Judy Hoch


#7

Hi Birgit, I see two areas to explore in your most detailed
description:

  1. Applying the firecoat before applying the flux. The firecoat is
    viscous enough to keep the pallion of solder floating above the metal
    being soldered. If the pallion is not in contact with the metal the
    solder will overheat in the flame before it finally sinks through to
    touch the metal and flow into the joint. Solder is weaker after being
    overheated. If the solder balls up before flowing then this may be
    the problem.

  2. Your rings are quite heavy in section with the join in the middle
    of straight part of the ‘D’. Bending the ring into roundness after
    soldering will indeed put enormous strain on the joint. My method of
    forming such a ring is to get it as round as possible by hammering
    or malleting on the ring stick without worrying too much about
    closing the gap or getting a perfect joint…yet. Closing the gap in
    heavy rings is surprisingly easy if you do it at near red heat using
    a pair of strong tweesers or tongs. The metal behaves like putty and
    has no springyness at all. The gap can be closed and the joint
    squeezed and pushed into perfect alignment while the ring is hot and
    lying on the soldering pad. Quench, then saw through the now closed
    joint to clean the faces and remove any gaps in the seam. I proceed
    from here in the following manner… place a pallion of solder inside
    the gap left by the saw cut, flux the joint, dry the flux and dip the
    ring into the firecoat, grip the ring with the tweezers or tongs so
    as to precisely and gently close the remianing gap when the solder
    melts. The ring will be pliable at the soldering heat of hard solder,
    so when the solder melts the gap will close with gentle pressure on
    the tweezers. The ring will need very little forming after soldering
    and the joint will easily stand up to the forces of further
    hammering.

Regards, Alastair


#8

Thank you all for your replies and help. The problem seems to be
resolved.

It looks like I did use a flame that used too little oxygen and I
oxidized my metal before the solder could flow. As a result the
solder flowed, but did not adhere to the metal. After it was pointed
out to me, I did notice that my flame did change to more orage all
by itself during the soldering process. Could be I had too little
pressure on my oxygen bottle, could be my regulator is going bad
again.

Just to clarify, the seam of the ring was closed tightly when I
soldered, but it opened up when I rounded the ring. Before rounding
the ring, there was a line of solder visible across the complete
solder seam, so it looked totally fine.

I am hoping that this is indeed the cause of the problem and it does
not happen again. It was quite nerve wrecking to suddenly not be
able to do my work anymore. So again, thank you all.


#9

Why don’t you try applying the solder to the OUTSIDE of the shank,
instead of inside since its the outside edge that’s failing. I
notice in the pics that the corners are holding, which indicates to
me that you might not have gotten flow right thru the full cross
section of the joint. The edges would normally get hotter than the
midsection so you’d get better penetration there, hence the corners
hold better. Your solder might be flowing along the outside of the
seam from the corners without going in very deep, away from the
corners. It might LOOK like flowthru but it might actually be
’flowaround’, to coin a phrase.

You might try stretching a fresh, failed joint til it breaks
completely and loupe the inside of the joint. You should be able to
see if you had sufficient flow. If the inside still looks filed or
milled, then you didn’t get good penetration. Besides its easier to
clean up excess solder on the outside.

I heat up the top of the ring away from the seam. As the metal gets
close to hot enough I move the flame underneath the ring, where the
seam is to pull the solder thru. 

If I interpret that correctly you are heating 180 degrees away from
the joint and then moving closer? Might be better to heat the whole
ring with a circular brushing motion, then bear down on the joint.
You’d want the joint to be the hottest part of the ring. I’m not a
fan of placing snippets in silver, too much chance of burning the
solder. I’d use a pick, the flux will tell you when to move the pick
in.

Hope something there is useful.


#10

Hello all,

Thank you all for your replies and help. The problem seems to be
resolved. 

Another typical failure that points to the danger of routine work.

Soldering becomes a “normal” operation and one is not thinking or
does not notice the small changes in a manipulation which is
performed every day and so often. We know what’s happening but don’t
see the small differents in a handling and as a result… we don’t
know what’s going on untill somebody point you out what the problem
is. Minor changes in manipulation, equipment not being maintained
properly, lack of time or whatever but they do make a difference.

Stay focused even if you’re a well trained and very skilled person.
One of the reasons why I keep-on reading these failure question, I
still learn from them even after so many years of practice.

Have fun and enjoy
Pedro