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Pitting in solder seams


#1
    A simple fundamental mistake many self taught jewelers make is
to use easy solders were you should be using a hard solder. Easy
solder is not easier to use. Hard solder is not hard to use. It
often makes a job more difficult as you have found out. Keep you
seam really tight and use the highest flow temperature solder
possible. For 14kyg sizing I recommend 14ky hard or 14ky weld. For
14kwg rings use 19kw weld or 20kw weld. This will help
dramatically. Other things to look for. Again, keep you seam really
tight. Keep your flux and flux brush clean. Be sure to use a boric
acid and alcohol dip and a secondary flux such as batterns directly
on the solder joint. Good luck John Sholl Littleton, Colorado 

This is highly confusing to me. Firstly, what is “19 or 20k weld”?
I have never heard of this grade of solder. Also, I thought that
only lower karat golds could be used as solders on a given object.
Please help me to clarify this for myself. I don’t want to
perpetuate any misif my previous understanding is
erroneous. Thanks.

Danny Rondeau


#2
   This is highly confusing to me.  Firstly, what is "19 or 20k
weld"? 

White gold solders are notorious for being less resistant to the
action of polishing compounds than the white golds themselves, so
sizing seams tend to polish out, leaving a distinct indented line.
the 19 or 20K white weld solders are indeed higher karat, but
formulated so that although they melt just barely below the 14K or
18K white golds, they’ve got good color match, and are hard enough to
resist polishing on a par with the gold, so the seams then look a lot
better than with lower karat solders. They’re called “weld” grades
because they melt just a little bit before the golds themselves, and
using them is almost like just fusing a joint without solder. Not so
useful for very delicate assemblies, unless you’ve got a great deal
of skill.

   Also, I thought that only lower karat golds could be used as
solders on a given object. 

That is true IF the “solder” you are using is simply a standard
gold alloy, such that the only difference between the gold you’re
assembling and the “solder” is that the solder has less gold. That
serves to lower the melting point, usually, so it’s then usable as a
solder. But it’s not a good one, many times, since normal gold
alloys aren’t formulated for the same melting and flowing
characteristics as solders.

Solders work because either the proportions of the componants of the
alloys are different from the parent alloy being soldered, or the
solder has different or additional metals in the alloy, to lower the
melting point of the solder. Most gold solders today used fall into
two classes, the repair grade solders, and the 'plumb" solders.
Repair grade solders are indeed often (but not always) lower in gold
content than the alloy they’re intended for. This sometimes allows
better color match, but usually it’s done to lower the flow temps
even more, or otherwise make the solder easier to use. The "Plumb"
solders are just that. they contain the same amount of gold as the
alloys they’re used with, and the lower melting point is achieved by
varying the composition of the other alloying metals without
changing the gold content. In some cases, Cadmium or zinc is added,
in others, well, other stuff is added, and usually the ratios of
silver to copper are played with too, to lower the melting point.
These sometimes, especially with easy grades, don’t match the color
as well as one could wish, but they are full karat, making
hallmarking/stamping possible. For this reason, most new jewelery
is assembled with “plumb” solders. The “weld” high karat grades of
white gold solders are special cases, formulated not just for flow
temperature and color, but also for hardness, which is seldom a
probem with yellow gold solders.


#3
    This is highly confusing to me.  Firstly, what is "19 or 20k
weld"? I have never heard of this grade of solder. Also, I thought
that only lower karat golds could be used as solders on a given
object. Please help me to clarify this for myself.  I don't want to
perpetuate any misif my previous understanding is
erroneous.  Thanks. 

Danny, Sorry about the confusion. You are for the most part right.
With yellow gold use 14k solder with 14k gold. Use 18k with 18k and
so on. But, always use the hardest solder possible. For example I
use hard for sizing seams or reshanks. Medium for bails, posts or
soldering in heads. Easy for repairs done on delicate portions of
rings that are too thin to take too much heat or areas that have
been previously worked on by other jewelers.

White gold is an exception. The 19k or 20k white solders are
available from all of the normal sources. ( Frie borel, Hoover
Strong, Stuller ect.) This solder will melt just below the melting
temperature of both 18k and 14k white gold. It creates a seam that
is ,if properly done, invisible. This solder is what I was trained
to use when sizing white gold rings and retipping white gold prongs.
It is more durable than other gold solders and less likely to bubble
when it flows on the tip. Also with white gold try using hard solder
where you would use medium and use easy where you would use medium
on yellow gold.

Easy solder can tarnish, fail for no apparent reason and it leaves
pits on seams. Easy solder is also more likely to “jump” to which
ever piece of metal gets to temperature first forcing you to apply
more solder creating a mess which needs cleaned up. Use it
sparingly. As for extra easy solder? I don’t even have any, no need.

I hope you try these tips. They will save you many headaches.

John Sholl
Littleton, Colorado