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Strength factor of different solders


#1

Hello everyone! My name is Jakob and I have a question regarding
types of solders. Ive been making jewelry for about 2 years now and I
have been pretty accustomed to the step soldering method as is often
taught to beginning metal smiths. (Hard, medium, easy, extra easy)
Well I know many people dislike easy solder because of its odd colour
etc. I am wondering about the strength factor of it all? Sometimes I
get out of hand making my fittings for my viking knit chains and many
soldering joins are present. My last soldering join is usually easy
or extra easy solder connecting the caps to the chain itself. Can
this solder handle stress like hard solder can? This is important to
me as I often make rather weighty pendants…


#2

Hi Jakob,

I learned this in first year.

The harder the solder the deeper the penetration into the
surrounding join.

I was taught to use the hardest solder I could to give the best
strength.

When a jeweller say they’re soldering they are actually welding with
the hard solders then brazing with the softer solders (osiwt).

If the bond between the metals secure you shouldn’t have any
problems.

Regards Charles A.


#3

Basically, the complete range has very similar tensile and shear
strengths, and strangely, some of the easy grades are actually
stronger than some of the hard grades. But the differences are not
enough to worry about.

By the way, did you know that you need a slightly higher temperature
to melt the solder in an existing joint?

You can exploit this fact by using the same grade near to an
existing joint without affecting the existing joint. The difference
is not great, but it certainly exists. But you do need more skill.

Regards, Gary Wooding


#4

Charles, Believe you have a mis-conception of the term welding.
Welding is when the metal on each side of a join is melted and
another metal is added to the melt to create a mixing action. When a
weld cures the new alloy in the join is stronger than that on each
side.

Fusing is when the metal on either side of a join is melted but no
additional metal is added resulting in a mating of the metals and
essentially creating a seamless piece.

When using silver or gold solder at any melting temp above 800 deg
(i.e. ‘hard’ soldering), the heat burns out the oxygen creating a
vacuum that sucks the solder into the join filling the boundry
around the grains. You are correct that the hardest solder is the
strongest but it is because it contains less alloy (i.e. copper) and
is close to the hardness of the metals being joined. Cheers, from Don
in SOFL.


#5
The harder the solder the deeper the penetration into the
surrounding join. 
I was taught to use the hardest solder I could to give the best
strength. 

I must, easy solders penetrate in to the metal much deeper. You ever
seen the holes easy solder can eat in work when slightly overheated?
There are a wide variety of solder formulas the tensile strength
varies with the formula. I find that the medium silver solder is
stronger than the hard from the same manufacturer. So generalities
like the hard solder is the strongest and penetrates furthest are
not necessarily true.

When a jeweller say they're soldering they are actually welding
with the hard solders then brazing with the softer solders (osiwt). 

No if the filler melts at a lower temperature than the parent metals
it is brazing, welding requires the melting of the parent metals not
an intermediate alloy.

If the bond between the metals secure you shouldn't have any
problems. 

Agreed

Regards,
Jim

James Binnion
James Binnion Metal Arts


#6
By the way, did you know that you need a slightly higher
temperature to melt the solder in an existing joint? 

This is true if you are soldering silver with silver solder, but
just the opposite is true if you are soldering copper alloys with
silver solder. Solder brass with silver solder and the joint will
melt at a lower temperature the second time.

This is because when silver solder flows it absorbs a little metal
from the material being joined. Higher concentrations of silver in
the solder alloy melt at a higher temperature. If the solder absorbs
a little more copper or copper and zinc as in the case of brass, the
melting temperature drops. Over-heating the solder joint will
exaggerate this effect.

I would presume the same is true with gold solder but I have never
soldered copper alloys with gold. Soldering silver to gold tends to
create a lower melting solder joint and can be very messy if you
overheat it.


#7
I was taught to use the hardest solder I could to give the best
strength. 

Good advice, but the largest contribution to the joint strength is
not the solder itself. Joint construction, heat application, and the
design itself are way more important.

Leonid Surpin
www.studioarete.com


#8
When using silver or gold solder at any melting temp above 800 deg
(i.e. 'hard' soldering), the heat burns out the oxygen creating a
vacuum that sucks the solder into the join filling the boundry
around the grains.

Don this not correct, the solder is “sucked” in by capillary
attraction there is no vacuum created.

James Binnion
James Binnion Metal Arts


#9

Depends on the carat value. I find 18K easy is much stronger than 9K
hard when used on 9K alloys.

The melting temps may be similar but the solder properties are
different. Colour matching favours the higher carat solder…better
to be too yellow than too pale.

Alastair


#10
Fusing is when the metal on either side of a join is melted but no
additional metal is added resulting in a mating of the metals and
essentially creating a seamless piece. 

It appears that I’ve been mis-informed about jewellery soldering :frowning:

Just goes to show you’re never too old to learn :wink:

Regards Charles A.


#11

It certainly works with silver solder and silver, and gold solder
and gold, I’ve exploited it many times. I also do model engineering
and can confirm that it also works with silver solder and copper. I
never tried it with silver solder and brass or bronze.

Regards, Gary Wooding


#12
You ever seen the holes easy solder can eat in work when slightly
overheated? 

Actually I haven’t, although I own easy solder, I am yet to find
myself in a situation to use it. I used hard, pretty much all the
time, and have only used medium on the rare occasion.

When a jeweller say they're soldering they are actually welding
with the hard solders then brazing with the softer solders
(osiwt). No if the filler melts at a lower temperature than the
parent metals it is brazing, welding requires the melting of the
parent metals not an intermediate alloy. 

That’s cool, like I said to Don, I’m never too old to learn, and I
can pass this on with confidence. Thanks for the
correction Jim, I like to pass on the right

Regards Charles A.


#13
It appears that I've been mis-informed about jewellery soldering
:-( Just goes to show you're never too old to learn ;-) 

While nomenclature, terms, standard descriptions, and all that are
needed for teaching, or posting to orchid, or sometimes for properly
understanding something in a book or article, in the workshop itself,
what matters is knowing how to do the stuff, not what to call it.

Cheers
Peter


#14
While nomenclature, terms, standard descriptions, and all that are
needed for teaching, or posting to orchid, or sometimes for
properly understanding something in a book or article, in the
workshop itself, what matters is knowing how to do the stuff, not
what to call it. 

True, and I did learn to cut dead straight after watching the
teacher’s technique for 5 minutes.

Mind you on this forum, one can get jumped on for not providing the
correct and I like to give good :slight_smile:

Regards Charles A.
P.S. I’m never offended if I’m told I’m wrong :wink: