Why my solder does not flow

Jewelry Discussion
21

What are you using to clean your piece? If you are using an
ultrasonic and trying to get the most out of the solution (in other
words you are a tightwad like me and can’t make yourself change it
because it’s expensive) that can cause soldering problems. Also,
sometimes solutions that aren’t made for the ultrasonic but are often
used as a cheap alternative, like Mr. Clean, don’t work as well as
specifically formulated ultrasonic solution and can go bad quickly
and can leave a microscopic film on the metal.

The metal must be chemically clean, not just look clean. Going from
sandpaper to flux with just a rinse of tap water won’t always do.
And as Peter says, salt water probably won’t help either. But who
knows? I’ve never tried it. Sounds like a good reason to go to the
beach.

From what you describe it definitely sounds like one of the three
basics, enough even heat, tight fit or cleaning. My bet is cleaning.
If you don’t have an ultrasonic or steamer, you might try a metal
cleaning (not etching) product used for preparation for painting. Try
you local auto paint supply place. There are several brands. Follow
the directions for bare metal painting.

Dave

22

This was exactly my problem when I first started posting to Orchid
last year. I’d successfully done lots of bezel to backplate settings,
then I tried to do the same thing but on a larger scale and it simply
wouldn’t work and I kept melting through the bezels I’d made.

I was given various bits of advice, one being to raise the piece up
onto a platform and heat from underneath, heating evenly and only
playing the flame onto the bezel on top of the sheet at the end,
once the backplate is good and hot enough.

However, I found that whilst this worked for some large settings, it
didn’t work for others and I discovered that it was because the
ambient air was cooling the metal down such that I could never get
enough heat into it. I solved this problem by heating the piece on
the soldering board/block again, using its heat absorbing and
reflecting properties to insulate the piece, thus retaining the heat
the torch was providing. This enabled me to get enough heat into the
piece eventually and allow the solder to flow. The important thing
with this method is to have the sheet/backplate quite a bit larger
than the size of the bezel so that you can play the flame on the
“extension” as someone else said, being careful not to get the bezel
too hot too soon. I play the heat around the board surrounding the
piece, then around the “extension”, then around the inside of the
bezel, then the “extension”, then the board, etc, etc, until the
piece is hot enough for the solder to flow.

Don’t worry if you run out of bezel wire - you can always make your
own from sheet. It’s good practice, cutting it, filing it, etc and
you might find that you actually prefer it to ready made bezel
strip. I don’t like bezel strip - I find that either it’s not thick
enough or it’s not the right width for the stones I want to set. I
custom cut all my bezels depending on the size of the stone. I used
to use 0.3mm thick sheet but my favourite thickness is 0.5mm sheet
for making bezels and I try to remove as little metal as possible
when finishing. My bearers (for faceted stones) are also made from
the 0.5mm sheet, which when bent and soldered inside the bezel gives
a very substantial shelf for the girdle of the stone to sit on.

Helen
UK
http://www.hillsgems.co.uk

23

Mo betta heat! Sterling silver melts at 1640 F. Hard solder flows
between 1375 and 1490 depending on the manufacturer.

For a bezel, you have a tiny area to solder your bezel together.
Lots of heat thrown at a tiny mass. You are probably using fine
silver bezel which has a higher melting temperature, but no matter.
It’s still a lot of heat directed at a small area which is thin.

Now you are soldering the bezel to a large amount of silver. I don’t
know your dimensions or mass of the metal, but here is the analogy.

Think of your stove. Take a tiny sauce pan that holds 1/4 cup of
water and put it on the stove and turn the heat up to high. If you
have gas or electric, won’t matter. In a few minutes that water will
be boiling away.

Now go get a huge stock pot, fill it with water and do the same
thing, but turn the heat down low. It will sit there and sit there
and do nothing. The mass of what you are heating is exceeding the
thermal capacity of the water. You need more heat to boil the water
and to match the mass. It will take longer even if your stove is on
high, but eventually it will get there.

For soldering a bezel, solder will flow towards heat. If your torch
is above the bezel and your metal and the flame pointing down, the
tiny mass in the bezel will heat up first and the solder will start
climbing up the bezel because solder flows to the hottest point.

If you take some crosslock tweezers (cheap push for mine here), hold
one end of your metal and bring your torch UNDERNEATH your highly
fluxed silver piece, your base metal (I call it parent) will heat up,
solder will flow downwards and if your fit is good between your bezel
and your parent metal, voila! The solder will run its course and it
will know exactly what to do and where to go.

Where to put those chips? Well, if you are setting a stone and
completely removing all the surrounding metal, put the chips on the
outside of the bezel. Remember, always solder so clean up is easy. IF
you have a highly decorated exterior piece, you will want to put the
chips on the inside.

How many chips? Depends on the size of the piece. For an area of 1
inch by 1 inch, I would use five really tiny chips. If it needs more,
then use more. Sometimes if you just clean the piece up and use the
existing solder you won’t need any more.

Size of solder chips? Tiny, itty, bitty, really, really tiny. Think
of a fire in a fireplace. You have a tiny glowing ember. IF you put a
small stick in the fire, the ember will catch and the stick will
burn. Now, go put a giant oak log on the ember. Will it catch and
burn? NO. You need to stoke that fire, add tiny pieces until it can
take a larger piece.

Remember, you don’t have to solder that bezel all at once. Just TACK
IT with a few tiny pieces so it won’t move. Clean it up, flux and go
after it again. You will be amazed how little you need.

When I teach soldering, I snip a piece in my hand and show it to my
students. They are in shock that such a tiny piece will work.

Exercise for soldering.

Here is a quick exercise for soldering.

Simple band ring. We’ve all made one but bear with me here.

  1. Form the band, say 18 sterling ga, 6mm wide x 65 mm long.

  2. make a good fit so no light is coming through. We don’t’ want
    “gaposis”.

  3. Flux your piece and make the ring stand up with the seam side
    down.

  4. cut a tiny, and I mean one tiny piece of hard solder. How tiny?
    Take your thumbs and index finger and bring them together, index to
    index and thumb to thumb and create a negative space in between.
    Close the gap with your fingers until just a tiny spec of light shows
    through. (those with long finger nails might have a tough time). That
    little light shining through should be the size of your solder chip.

  5. load your chip onto the center of the seam. Allow your flux to
    dry.

  6. Now, take your flame and aim it just to the right of the seam.
    Now here is my little saying. “Go around and around and take a little
    vacation”. That means move your flame on the band ring around
    clockwise, and then counter clockwise and when you reach the seam,
    stay there for a bit. Keep repeating and pretty soon, your solder
    will melt right into the seam.

By doing this, you have allowed the metal to heat up evenly, while
the center seam receives additional heat. The surrounding heat is
driven down to the seam and the solder has nothing more to do except
to flow.

Karen Christians
Waltham, MA
http://www.cleverwerx.com