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IT and every other kind of solder basics


#1

OK, I’m an absolute beginner. I’m just winding up my very first
silversmithing class at the local University and at this point I’m
very confused.

If I understand correctly, “eutectic” means an alloy of two (or
more?) me tals mixed in such a way that the resulting metal has a
melting point that’s different from either/all of the component
metals. Am I right so far?

And “IT” (I think the acronym stands for “Incredibly Tough”) solder
has a melting point higher than “Hard”? And you want this because in
enameling you’re going to put your piece (hooray for those
complaining about grammatical, spelling and homonym errors) in an
oven that might melt even Hard solder?

OK, so if Easy, Medium, Hard and IT are all silver-copper alloys,
what’s the critical factor in determining melting and flow points -
the copper content? The ratio? The phase of the moon?

Do you use the same solder for joining copper as you do for silver?

What do you use for gold - solder containing gold? What alloying
metal, and are there grades of solder for gold, too?

Is there such a thing as welding silver, copper and/or gold? If so,
it seems like spot welding would be a whole lot easier and neater for
small joins than soldering?

I’m a devoted fan of both Bench Tube and American Chopper.

Feel free to mock the newbie!

Mike Rudahl
Albuqerque, NM - “the turquoise chip inlay capital of the Universe”


#2
If I understand correctly, "eutectic" means an alloy of two (or
more?) me tals mixed in such a way that the resulting metal has a
melting point that's different from either/all of the component
metals. Am I right so far? 

No, To be a eutectic alloy it has to meet a few parameters. One, it
must transition from solid to liquid with no intermediate mushy
phase where there is both solid and liquid present. All alloys except
eutectics have an intermediate phase where both solid and liquid
phases are present. Two, the melting point of a eutectic alloy must
be the lowest melting point of the two metals being alloyed. Three is
a little tougher to understand without some metallurgy background but
a eutectic alloy will solidify as a two phase solid. In the case of
silver and copper it means the eutectic alloy when it solidifies
consists of some crystals that are mostly silver with a small amount
(less than 8.8% copper) the alpha phase, and the balance of the
crystals are mostly copper with a small amount (less than 8 %)
silver the beta phase. In other eutectic alloys the percentages will
be different but they will all solidify as two phase solids.

And "IT" (I think the acronym stands for "Incredibly Tough")
solder has a melting point higher than "Hard"? And you want this
because in enameling you're going to put your piece (hooray for
those complaining about grammatical, spelling and homonym errors)
in an oven that might melt even Hard solder? 

No, Intense Temperature. Silver IT solder should not be used for
enameling as it contains zinc which will cause problems with the
enamel. You should use eutectic alloy solder wherever enamel and
solder will come in contact with each other

OK, so if Easy, Medium, Hard and IT are all silver-copper alloys,
what's the critical factor in determining melting and flow points
- the copper content? The ratio? The phase of the moon? 

The ratio of silver to copper to zinc is what determines the melting
points and flow points. To gain a basic understanding of this get
Mark Grimwade’s book “Introduction to Precious Metals, Metallurgy for
Jewelers and Silversmiths”

Do you use the same solder for joining copper as you do for
silver? 

mostly, there are a couple of copper phosphorous solders that can be
used to solder copper but they tend to be brittle and prone to
discoloration

What do you use for gold - solder containing gold? What alloying
metal, and are there grades of solder for gold, too? 

Gold solders come in many karat values and colors with most being
gold, silver,copper zinc alloys although some are still made with
cadmium also some use indium or gallium to lower the melting point

Is there such a thing as welding silver, copper and/or gold? If
so, it seems like spot welding would be a whole lot easier and
neater for small joins than soldering? 

Yes lasers are used to do small neat welds and TIG can be used to
make larger welds

James Binnion
James Binnion Metal Arts


#3

Wow.

OK, Jim answers a lot of emails every day, posts a lot on Orchid,
makes a LOT of rings, researches and improves technical process for
mokume gane production, and still takes the time to answer basic
questions using good grammar and formatting.

To mix up a couple of different threads, is there any remaining
argument that presentation matters? Given a choice between two
people presenting who do you turn to?

100% of the time, I read the answers from the people who are
considerate, demonstrate their knowledge rather than profess it, do
not condescend or belittle, and who present their knowledge in a
lucid and well formed manner.

I scan the list of posts on Orchid for a few names, Jim’s among
them, and read every post they put up regardless of whether it was a
topic I’ve been following or not.

Thanks to those of you who take the time to post in this manner.